Source: https://patents.google.com/patent/US20040022237A1/en
Timestamp: 2019-08-21 23:39:03
Document Index: 461922123

Matched Legal Cases: ['arty 102', 'arty 120', 'arty 122', 'arty 124', 'arty 120', 'arty 122', 'arty 124', 'arty 120', 'arty 124', 'arty 122', 'arty 120', 'arty 102', 'arty 120', 'arty 102', 'arty 102', 'arty 120', 'arty 102', 'arty 102', 'arty 102', 'arty 120', 'arty 102', 'arty 102', 'arty 120', 'arty 102', 'arty 102', 'arty 102', 'arty 102', 'arty 102', 'arty 120', 'arty 120', 'arty 102', 'arty 102', 'arty 120', 'arty 102', 'arty 120', 'arty 102', 'arty 102', 'arty 102', 'arty 102', 'arty 102', 'arty 120', 'arty 120', 'arty 120', 'arty 102', 'arty 120', 'arty 122', 'arty 124']

US20040022237A1 - Voice over data telecommunications network architecture - Google Patents
US20040022237A1
US20040022237A1 US10/366,061 US36606103A US2004022237A1 US 20040022237 A1 US20040022237 A1 US 20040022237A1 US 36606103 A US36606103 A US 36606103A US 2004022237 A1 US2004022237 A1 US 2004022237A1
US10/366,061
US7564840B2 (en
2003-02-12 Application filed by Level 3 Communications LLC filed Critical Level 3 Communications LLC
2004-02-05 Publication of US20040022237A1 publication Critical patent/US20040022237A1/en
2005-10-24 Assigned to LEVEL 3 COMMUNICATIONS, INC. reassignment LEVEL 3 COMMUNICATIONS, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: DUGAN, ANDREW JOHN, STEELE, RICK D., WANG, JIN-GEN, BAKER, BRUCE W., PETERSON, JON, HIGGINS, STEVEN P., ELLIOTT, ISAAC K., HERNANDEZ, ROBERT L., LEWIS, SHAWN M., MITCHELL, JONATHAN S., STEARNS, HAROLD, TERPSTRA, RICH, WAIBEL, RAY, ZIMMERER, ERIC, OWEN, KRAIG
2009-07-21 Publication of US7564840B2 publication Critical patent/US7564840B2/en
This application is a continuation of U.S. patent application Ser. No. 09/197,203, entitled VOICE OVER DATA TELECOMMUNICATION NETWORK ARCHITECTURE, filed Nov. 20, 1998. This application of common assignee contains a related disclosure to U.S. Pat. No. 6,442,169, entitled “System and Method for Bypassing Data from Egress Facilities.” Both U.S. patent application Ser. No. 09/197,203 and U.S. Pat. No. 6,442,169 are incorporated herein by reference in their entirety.[0001]
The present invention relates generally to telecommunications networks and, more particularly, to a system and method for providing transmission for voice and data traffic over a data network, including the signaling, routing and manipulation of such traffic. [0003]
The present invention relates to telecommunications, and in particular to voice and data communication operating over a data network. The Public Switched Telephone Network (PSTN) is a collection of different telephone networks owned by different companies which have for many years provided telephone communication between users of the network. Different parts of the PSTN network use different transmission media and compression techniques. [0005]
Most long distance calls are digitally coded and transmitted along a transmission line such as a T1 line or fiber optic cable, using circuit switching technology to transmit the calls. Such calls are time division multiplexed (TDM) into separate channels, which allow many calls to pass over the lines without interacting. The channels are directed independently through multiple circuit switches from an originating switch to a destination switch. Using conventional circuit switched communications, a channel on each of the T1 lines along which a call is transmitted is dedicated for the duration of the call, whether or not any information is actually being transmitted over the channel. The set of channels being used by the call is referred to as a “circuit.”[0006]
Telecommunications networks were originally designed to connect one device, such as a telephone, to another device, such as a telephone, using switching services. As previously mentioned, circuit-switched networks provide a dedicated, fixed amount of capacity (a “circuit”) between the two devices for the entire duration of a transmission session. Originally, this was accomplished manually. A human operator would physically patch a wire between two sockets to form a direct connection from the calling party to the called party. More recently, a circuit is set up between an originating switch and a destination switch using a process known as signaling. [0007]
Signaling sets up, monitors, and releases connections in a circuit-switched system. Various signaling methods have been devised. Telephone systems formerly used in-band signaling to set up and tear down calls. Signals of an in-band signaling system are passed through the same channels as the information being transmitted. Early electromechanical switches used analog or multi-frequency (MF) in-band signaling. Thereafter, conventional residential telephones used in-band dual-tone multiple frequency (DTMF) signaling to connect to an end office switch. Here, the same wires (and frequencies on the wires) were used to dial a number (using pulses or tones), as are used to transmit voice information. However, in-band signaling permitted unscrupulous callers to use a device such as a whistle to mimic signaling sounds to commit fraud (e.g., to prematurely discontinue billing by an interexchange carrier (IXC), also known as a long distance telephone company). [0008]
More recently, to prevent such fraud, out-of-band signaling systems were introduced. Out-of-band signaling uses a signaling network that is separate from the circuit switched network used for carrying the actual call information. For example, integrated services digital network (ISDN) uses a separate channel, a data (D) channel, to pass signaling information out-of-band. Common Channel Interoffice Signaling (CCIS) is another network architecture for out-of-band signaling. A popular version of CCIS signaling is Signaling System 7 (SS7). SS7 is an internationally recognized system optimized for use in digital telecommunications networks. [0009]
SS7 out-of-band signaling provided additional benefits beyond fraud prevention. For example, out-of-band signaling eased quick adoption of advanced features (e.g., caller id) by permitting modifications to the separate signaling network. In addition, the SS7 network enabled long distance “Equal Access” (i.e., 1+ dialing for access to any long distance carrier) as required under the terms of the modified final judgment (MFJ) requiring divestiture of the Regional Bell Operating Companies (RBOCs) from their parent company, AT&T. [0010]
An SS7 network is a packet-switched signaling network formed from a variety of components, including Service Switching Points (SSPs), Signaling Transfer Points (STPs) and Service Control Points (SCPs). An SSP is a telephone switch which is directly connected to an SS7 network. All calls must originate in or be routed through an SSP. Calls are passed through connections between SSPs. An SCP is a special application computer which maintains information in a database required by users of the network. SCP databases may include, for example, a credit card database for verifying charge information or an “800” database for processing number translations for toll-free calls. STPs pass or route signals between SSPs, other STPs, and SCPs. An STP is a special application packet switch which operates to pass signaling information. [0011]
The components in the SS7 network are connected together by links. Links between SSPs and STPs can be, for example, A, B, C, D, E or F links. Typically, redundant links are also used for connecting an SSP to its adjacent STPs. Customer premises equipment (CPE), such as a telephone, are connected to an SSP or an end office (EO) switch. [0012]
To initiate a call in an SS7 telecommunications network, a calling party using a telephone connected to an originating EO switch, dials a telephone number of a called party. The telephone number is passed from the telephone to the SSP at the originating EO (referred to as the “ingress EO”) of the calling party's local exchange carrier (LEC). A LEC is commonly referred to as a local telephone company. First, the SSP will process triggers and internal route rules based on satisfaction of certain criteria. Second, the SSP will initiate further signaling messages to another EO or access tandem (AT), if necessary. The signaling information can be passed from the SSP to STPs, which route the signals between the ingress EO and the terminating end office, or egress EO. The egress EO has a port designated by the telephone number of the called party. The call is set up as a direct connection between the EOs through tandem switches if no direct trunking exists or if direct trunking is full. If the call is a long distance call, i.e., between a calling party and a called party located in different local access transport areas (LATAs), then the call is connected through an inter exchange carrier (IXC) switch of any of a number of long distance telephone companies. Such a long distance call is commonly referred to as an inter-LATA call. LECs and IXCs are collectively referred to as the previously mentioned public switched telephone network (PSTN). [0013]
Emergence of competitive LECs (CLECs) was facilitated by passage of the Telecommunications Act of 1996, which authorized competition in the local phone service market. Traditional LECs or RBOCs are now also known as incumbent LECs (ILECs). Thus, CLECs compete with ILECs in providing local exchange services. This competition, however, has still not provided the bandwidth necessary to handle the large volume of voice and data communications. This is due to the limitations of circuit switching technology which limits the bandwidth of the equipment being used by the LECs, and to the high costs of adding additional equipment. [0014]
Since circuit switching dedicates a channel to a call for the duration of the call, a large amount of switching bandwidth is required to handle the high volume of voice calls. This problem is exacerbated by the fact that the LECs must also handle data communications over the same equipment that handle voice communications. [0015]
If the PSTN were converted to a packet-switched network, many of the congestion and limited bandwidth problems would be solved. However, the LECs and IXCs have invested large amounts of capital in building, upgrading and maintaining their circuit switched networks (known as “legacy” networks) and are unable or unwilling to jettison their legacy networks in favor of the newer, more powerful technology of packet switching. Accordingly, a party wanting to build a packet-switched network to provide voice and data communications for customers must build a network that, not only provides the desired functionality, but also is fully compatible with the SS7 and other, e.g., ISDN and MF, switching networks of the legacy systems. [0016]
Currently, internets, intranets, and similar public or private data networks that interconnect computers generally use packet switching technology. Packet switching provides for more efficient use of a communication channel as compared to circuit switching. With packet switching, many different calls (e.g., voice, data, video, fax, Internet, etc.) can share a communication channel rather than the channel being dedicated to a single call. For example, during a voice call, digitized voice information might be transferred between the callers only 50% of the time, with the other 50% being silence. For a data call, information might be transferred between two computers 10% of the time. With a circuit switched connection, the voice call would tie-up a communications channel that may have 50% of its bandwidth being unused. Similarly, with the data call, 90% of the channel's bandwidth may go unused. In contrast, a packet-switched connection would permit the voice call, the data call and possibly other call information to all be sent over the same channel. [0017]
Packet switching breaks a media stream into pieces known as, for example, packets, cells or frames. Each packet is then encoded with address information for delivery to the proper destination and is sent through the network. The packets are received at the destination and the media stream is reassembled into its original form for delivery to the recipient. This process is made possible using an important family of communications protocols, commonly called the Internet Protocol (IP). [0018]
In a packet-switched network, there is no single, unbroken physical connection between sender and receiver. The packets from many different calls share network bandwidth with other transmissions. The packets are sent over many different routes at the same time toward the destination, and then are reassembled at the receiving end. The result is much more efficient use of a telecommunications network than could be achieved with circuit-switching. [0019]
Recognizing the inherent efficiency of packet switched data networks such as the Internet, attention has focused on the transmission of voice information over packet-switched networks. However, such systems are not compatible with the legacy PSTN and therefore are not convenient to use. [0020]
One approach that implements voice communications over an IP network requires that a person dial a special access number to access an IP network. Once the IP network is accessed, the destination or called number can be dialed. This type of call is known as a gateway-type access call. [0021]
Another approach involves a user having a telephone that is dedicated to an IP network. This approach is inflexible since calls can only be made over the IP network without direct access to the PSTN. [0022]
What is needed is a system and method for implementing packet-switched communications for both voice calls and data calls that do not require special access numbers or dedicated phones and permit full integration with the legacy PSTN. [0023]
The present invention is a system and method for communicating both voice and data over a packet-switched network that is adapted to coexist and communicate with a PSTN. The system permits efficient packet switching of voice calls and data calls from a PSTN carrier such as, for example, a LEC, IXC, a customer facility or a direct IP connection on the data network to any other LEC, IXC, customer facility or direct IP connection. For calls from a PSTN carrier, e.g., LEC or IXC, the invention receives signaling from the legacy SS7 signaling network or the ISDN D-channel or from inband signaling trunks. For calls from a customer facility, data channel signaling or inband signaling is received. For calls from a direct IP connection on the data network, signaling messages can travel over the data network. On the call destination side, similar signaling schemes are used depending on whether the called party is on a PSTN carrier, a customer facility or a direct IP connection to the data network. [0024]
The system includes soft switch sites, gateway sites, a data network, a provisioning component a network event component and a network management component. The system of the invention interfaces with customer facilities (e.g., a PBX), carrier facilities (e.g., a PSTN carrier, a LEC (e.g., ILECs and CLECs), an independent telephone company (ITC), an IXC, an intelligent peripheral or an enhanced service provider (ESP)) and legacy signaling networks (e.g., SS7) to handle calls between any combination of on-network and off-network callers. [0025]
The soft switch sites provide the core call processing for the voice network architecture. Each soft switch site can process multiple types of calls including calls originating from or terminating at off-network customer facilities as well as calls originating from or terminating at on-network customer facilities. Each soft switch site receives signaling messages from and sends signaling messages to the signaling network. The signaling messages can include, for example, SS7, integrated services digital network (ISDN) primary rate interface (PRI) and in-band signaling messages. Each soft switch site processes these signaling messages for the purpose of establishing new calls through the data network and tearing down existing calls and in-progress call control functions. Signaling messages can be transmitted between any combination of on-network and off-network callers. [0026]
Signaling messages for a call which either originates off-network or terminates off-network can be carried over the out-of-band signaling network of the PSTN via the soft switch sites. Signaling messages for a call which both originates on-network and terminates on-network can be carried over the data network rather than through the signaling network. [0027]
The gateway sites originate and terminate calls between calling parties and called parties through the data network. The soft switch sites control or manage the gateway sites. In a preferred embodiment, the soft switch sites use a protocol such as, for example, the Internet Protocol Device Control (IPDC) protocol, to manage network access devices in the gateway sites to request the set-up and tear-down of calls. However, other protocols could be used, including, for example, network access server messaging interface (NMI) and the ITU media gateway control protocol (MGCP). [0028]
The gateway sites can also include network access devices to provide access to network resources (i.e., the communication channels or circuits that provide the bandwidth of the data network). The network access devices can be referred to generally as access servers or media gateways. Exemplary access servers or media gateways are trunking gateways (TGs), access gateways (AGs) and network access servers (NASs). The gateway sites provide for transmission of both voice and data traffic through the data network. The gateway sites also provide connectivity to other telecommunications carriers via trunk interfaces to carrier facilities for the handling of voice calls. The trunk interfaces can also be used for the termination of dial-up modem data calls. The gateway sites can also provide connectivity via private lines and dedicated access lines (DALs), such as T1 or ISDN PRI facilities, to customer facilities. [0029]
The data network connects one or more of the soft switch sites to one or more of the gateway sites. The data network routes data packets through routing devices (e.g., routers) to destination sites (e.g., gateway sites and soft switch sites) on the data network. For example, the data network routes internet protocol (IP) packets for transmission of voice and data traffic from a first gateway site to a second gateway site. The data network represents any art-recognized data network including the global Internet, a private intranet or internet, a frame relay network, and an asynchronous transfer mode (ATM) network. [0030]
The network event component collects call events recorded at the soft switch sites. Call event records can be used, for example, for fraud detection and prevention, and billing. [0031]
The provisioning event component receives provisioning requests from upstream operational support services (OSS) systems such as, for example, for order-entry, customer service and customer profile changes. The provisioning component distributes provisioning data to appropriate network elements and maintains data synchronization, consistency, and integrity across multiple soft switch sites. [0032]
The network management component includes a network operations center (NOC) for centralized network management. Each network element (NE) (e.g., soft switch sites, gateway sites, provisioning, and network event components, etc.) generates simple network management protocol (SNMP) events or alerts. The NOC uses the events generated by each network element to determine the health of the network and to perform other network management functions. [0033]
In a preferred embodiment, the invention operates as follows to process, for example, a long distance call (also known as a 1+ call). First, a soft switch site receives an incoming call signaling message from the signaling network. The soft switch site determines the type of call by performing initial digit analysis on the dialed number. Based upon the information in the signaling message, the soft switch site analyzes the initial digit of the dialed number of the call and determines that it is a 1+ call. The soft switch site then queries a customer profile database to retrieve the originating trigger plan associated with the calling customer. The query can be made using, for example, the calling party number provided in the signaling message from the signaling network. This look-up in the customer profile database returns subscription information. For example, the customer profile may indicate that the calling party has subscribed to an account code verification feature that requires entry of an account code before completion of the call. In this case, the soft switch site will instruct the gateway site to collect the account code digits entered by the calling party. Assuming that the gateway site collects the correct number of digits, the soft switch site can use the customer profile to determine how to process the received digits. For account code verification, the soft switch site verifies the validity of the received digits. [0034]
Verification can result in the need to enforce a restriction, such as a class of service (COS) restriction (COSR). In this example, the soft switch site can verify that the account code is valid, but that it requires that an intrastate COSR should be enforced. This means that the call is required to be an intrastate call to be valid. The class of service restriction logic can be performed within the soft switch site using, for example, pre-loaded local access and transport areas (LATAs) and state tables. The soft switch would then allow the call to proceed if the class of service requested matches the authorized class of service. For example, if the LATA and state tables show that the LATA of the originating party and the LATA of the terminating party are in the same state, then the call can be allowed to proceed. The soft switch site then completes customer service processing and prepares to terminate the cal. At this point, the soft switch site has finished executing all customer service logic and has a 10-digit dialed number that must be terminated. To accomplish the termination, the soft switch site determines the terminating gateway. The dialed number (i.e., the number of the called party dialed by the calling party) is used to select a termination on the data network. This termination may be selected based on various performance, availability or cost criteria. The soft switch site then communicates with a second soft switch site associated with the called party to request that the second soft switch site allocate a terminating circuit or trunk group in a gateway site associated with the called party. One of the two soft switch sites can then indicate to the other the connections that the second soft switch site must make to connect the call. The two soft switch sites then instruct the two gateway sites to make the appropriate connections to set up the call. The soft switch sites send messages to the gateway sites through the data network using, for example, IPDC protocol commands. Alternately, a single soft switch can set up both the origination and termination. [0035]
The present invention provides a number of important features and advantages. First, the invention uses application logic to identify and direct incoming data calls straight to a terminating device. This permits data calls to completely bypass the egress end office switch of a LEC. This results in significant cost savings for an entity such as an internet service provider (ISP), ILEC, or CLEC. This decrease in cost results partially from bypass of the egress ILEC end office switch for data traffic. [0036]
A further advantage for ISPs is that they are provided data in the digital form used by data networks (e.g., IP data packets), rather than the digital signals conventionally used by switched voice networks (e.g., PPP signals). Consequently, the ISPs need not perform costly modem conversion processes that would otherwise be necessary. The elimination of many telecommunications processes frees up the functions that ISPs, themselves, would have to perform to provide Internet access. [0037]
Another advantage of the present invention is that voice traffic can be transmitted transparently over a packet-switched data network to a destination on the PSTN. [0038]
Yet another advantage of the invention is that a very large number of modem calls can be passed over a single channel of the data network, including calls carrying media such as voice, bursty data, fax, audio, video, or any other data formats. [0039]
Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying figures.[0040]
The present invention will be described with reference to the accompanying figures, wherein: [0041]
FIG. 1 is a high level view of the Telecommunications Network of the present invention; [0042]
FIG. 2A is an intermediate level view of the Telecommunications Network of the present invention; [0043]
FIG. 2B is an intermediate level operational call flow of the present invention; [0044]
FIG. 3 is a specific example embodiment of the telecommunications network including three geographically diverse soft switch sites and multiple geographically diverse or collocated gateway sites; [0045]
FIG. 4A depicts a block diagram illustrating the interfaces between a soft switch and the remaining components of a telecommunications network; [0046]
FIG. 4B provides a Soft Switch Object Oriented Programming (OOP) Class Definition; [0047]
FIG. 4C provides a Call OOP Class Definition; [0048]
FIG. 4D provides a Signaling Messages OOP Class Definition; [0049]
FIG. 4E provides an IPDC Messages OOP Class Definition; [0050]
FIG. 4F depicts a block diagram of interprocess communication including the starting of a soft switch command and control functions by a network operations center; [0051]
FIG. 4G depicts a block diagram of soft switch command and control startup by a network operations center sequencing diagram; [0052]
FIG. 4H depicts a block diagram of soft switch command and control registration with configuration server sequencing diagram; [0053]
FIG. 4I depicts a block diagram of soft switch accepting configuration information from configuration server sequencing diagram; [0054]
FIG. 5A depicts a detailed block diagram of an exemplary soft switch site including two SS7 Gateways communicating with a plurality of soft switches which are in turn communicating with a plurality of Gateway sites; [0055]
FIG. 5B provides a Gateway Messages OOP Class Definition; [0056]
FIG. 5C depicts a block diagram of interprocess communication including soft switch interaction with SS7 gateways; [0057]
FIG. 5D depicts a block diagram of interprocess communication including an access server signaling a soft switch to register with SS7 gateways; [0058]
FIG. 5E depicts a block diagram of a soft switch registering with SS7 gateways sequencing diagram; [0059]
FIG. 6A depicts an Off-Switch Call Processing Abstraction Layer for interfacing with a plurality of on-network and off-network SCPs; [0060]
FIG. 6B depicts an Intelligent Network Component (INC) Architecture; [0061]
FIG. 6C depicts an INC architecture including On-net Services Control Points (SCPs); [0062]
FIG. 6D depicts an INC architecture including On-net and Off-net SCPs and customer Automatic Call Distributors (ACDs); [0063]
FIG. 7A provides a Configuration Server OOP Class Definition; [0064]
FIG. 7B depicts a block diagram of interprocess communication including soft switch interaction with configuration server; [0065]
FIG. 8A depicts Route Server Support for a Soft Switch Site including a plurality of collocated or geographically diverse route servers, soft switches, and Trunking Gateway and Access gateway sites; [0066]
FIG. 8B provides a Route Server OOP Class Definition; [0067]
FIG. 8C provides a Route Objects OOP Class Definition; [0068]
FIG. 8D provides a Pools OOP Class Definition; [0069]
FIG. 8E provides a Circuit Objects OOP Class Definition; [0070]
FIG. 8F depicts a block diagram of interprocess communication including soft switch interaction with route server (RS); [0071]
FIG. 9 depicts a block diagram of an exemplary Regional Network Event Collection Point Architecture (RNECP) including a master data center having a plurality of master network event database servers; [0072]
FIG. 10A depicts a detailed block diagram of an exemplary gateway site; [0073]
FIG. 10B depicts a block diagram of interprocess communication including soft switch interaction with access servers; [0074]
FIG. 11A depicts a detailed block diagram of an exemplary Trunking Gateway High-Level Functional Architecture; [0075]
FIG. 11B depicts a detailed flow diagram overviewing a Gateway Common Media Processing Component on the Ingress side of a trunking gateway; [0076]
FIG. 11C depicts a detailed flow diagram overviewing a Gateway Common Media Processing Component on the Egress side of a trunking gateway; [0077]
FIG. 12 depicts a detailed block diagram of an exemplary Access Gateway High-Level Functional Architecture; [0078]
FIG. 13 depicts a detailed block diagram of an exemplary Network Access Server High-Level functional architecture; [0079]
FIG. 14 depicts an exemplary digital cross connect system (DACS); [0080]
FIG. 15 depicts an exemplary Announcement Server Component Interface Design; [0081]
FIG. 16A depicts an exemplary data network interconnecting a plurality of gateway sites and a soft switch site; [0082]
FIG. 16B depicts a exemplary logical view of an Asynchronous Transfer Mode (ATM) network; [0083]
FIG. 17A depicts an exemplary signaling network including a plurality of signal transfer points (STPs) and SS7 gateways; [0084]
FIG. 17B depicts another exemplary embodiment showing connectivity to an SS7 signaling network; [0085]
FIG. 17C depicts a block diagram of an SS7 signaling network architecture; [0086]
FIG. 18 depicts a block diagram of the provisioning and network event components; [0087]
FIG. 19A depicts a block diagram of a data distributor in communication with a plurality of voice network elements; [0088]
FIG. 19B depicts a more detailed description of a data distributor architecture including voice network elements and upstream operational support services applications; [0089]
FIG. 19C depicts an exemplary embodiment of a data distributor and voice network elements; [0090]
FIG. 19D depicts a block diagram of provisioning interfaces into the SCPs from the data distributor; [0091]
FIG. 19E illustrates a data distributor including BEA M3, a CORBA-compliant interface server [0092] 1936 with an imbedded TUXEDO layer;
FIG. 19F depicts a detailed example embodiment block diagram of the BEA M3 data distributor of the provisioning element; [0093]
FIG. 19G depicts a block diagram illustrating a high level conceptual diagram of the BEA M3 CORBA-compliant interface; [0094]
FIG. 19H depicts a block diagram illustrating additional components of the high level conceptual diagram of the BEA M3 CORBA-compliant interface; [0095]
FIG. 19I depicts a block diagram illustrating a data distributor sending data to configuration server sequencing diagram; [0096]
FIG. 20 depicts a block diagram of a Master Network Event Database (MNEDB) interfacing to a plurality of database query applications; [0097]
FIG. 21A depicts an exemplary network management architecture; [0098]
FIG. 21B depicts an outage recovery scenario illustrating the occurrence of a fiber cut, latency or packet loss failure in the Data Network; [0099]
FIG. 21C depicts an outage recovery scenario including a complete-gateway site outage; [0100]
FIG. 21D further depicts an outage recovery scenario including a complete-gateway site outage; [0101]
FIG. 21E depicts an outage recovery scenario including a complete soft switch site outage; [0102]
FIG. 21F further depicts an outage recovery scenario including a complete soft switch site outage; [0103]
FIG. 21G depicts a block diagram of interprocess communication including a NOC communicating with a soft switch; [0104]
FIG. 22A depicts a high-level operational call flow; [0105]
FIG. 22B depicts a more detailed call flow; [0106]
FIG. 22C depicts an even more detailed call flow; [0107]
FIG. 23A depicts an exemplary voice call originating and terminating via SS7 signaling on a Trunking Gateway; [0108]
FIG. 23B depicts an exemplary data call originating on a SS7 trunk on a trunking gateway (TG); [0109]
FIG. 23C depicts an exemplary voice call originating on a SS7 trunk on a trunking gateway and terminating via access server signaling on an access gateway (AG); [0110]
FIG. 23D depicts an exemplary voice call originating on an SS7 trunk on a trunking gateway and terminating on an announcement server (ANS); [0111]
FIG. 24A depicts an exemplary voice call originating on an SS7 trunk on a network access server and terminating on a trunking gateway; [0112]
FIG. 24B Data Call originating on an SS7 trunk and terminating on a NAS; [0113]
FIG. 24C depicts an exemplary voice call originating on an SS7 trunk on a NAS and terminating via access server signaling on an AG; [0114]
FIG. 24D depicts an exemplary data call on a NAS with callback outbound reorigination; [0115]
FIG. 25A depicts an exemplary voice call originating on access server trunks on an AG and terminating on access server trunks on an AG; [0116]
FIG. 25B depicts an exemplary data call on an AG; [0117]
FIG. 25C depicts an exemplary voice call originating on access server trunks on an AG and terminating on SS7 signaled trunks on a TG; [0118]
FIG. 25D depicts an exemplary outbound data call from a NAS via access server signaling to an AG; [0119]
FIG. 26A depicts a more detailed diagram of message flow for an exemplary voice call received over a TG; [0120]
FIG. 26B depicts a more detailed diagram of message flow for an exemplary voice call received over a NAS; [0121]
FIG. 26C depicts a more detailed diagram of message flow for an exemplary data call over a NAS; [0122]
FIGS. [0123] 27-57 depict detailed sequence diagrams demonstrating component intercommunication during a voice call received on a NAS or TG or a data call received on a NAS;
FIG. 27 depicts a block diagram of a call flow showing a soft switch accepting a signaling message from an SS7 gateway sequencing diagram; [0124]
FIG. 28 depicts a block diagram of a call flow showing a soft switch getting a call context message from an IAM signaling message sequencing diagram; [0125]
FIG. 29A depicts a block diagram of a call flow showing a soft switch processing an LAM signaling message including sending a request to a route server sequencing diagram; [0126]
FIG. 29B depicts a block diagram of a call flow showing a soft switch starting processing of a route request sequencing diagram; [0127]
FIG. 30 depicts a block diagram of a call flow showing a route server determining a domestic route sequencing diagram; [0128]
FIG. 31 depicts a block diagram of a call flow showing a route server checking availability of potential terminations sequencing diagram; [0129]
FIG. 32 depicts a block diagram of a call flow showing a route server getting an originating route node sequencing diagram; [0130]
FIG. 33A depicts a block diagram of a call flow showing a route server calculating a domestic route for a voice call sequencing diagram; [0131]
FIG. 33B depicts a block diagram of a call flow showing a route server calculating a domestic route for a voice call sequencing diagram; [0132]
FIG. 34 depicts a block diagram of a call flow showing a soft switch getting a call context from a route response from a route server sequencing diagram; [0133]
FIG. 35 depicts a block diagram of a call flow showing a soft switch processing an IAM message including sending an IAM to a terminating network sequencing diagram; [0134]
FIG. 36 depicts a block diagram of a call flow showing a soft switch processing an ACM message including the sending an ACM to an originating network sequencing diagram; [0135]
FIG. 37 depicts a block diagram of a call flow showing a soft switch processing an ACM message including the setup of access devices sequencing diagram; [0136]
FIG. 38 depicts a block diagram of a call flow showing an example of how a soft switch can process an ACM sending an RTP connection message to the originating access server sequencing diagram; [0137]
FIG. 39 depicts a block diagram of a call flow showing a soft switch processing an ANM message sending the ANM to the originating SS7 gateway sequencing diagram; [0138]
FIG. 40 depicts a block diagram of a call teardown flow showing a soft switch processing an REL message with the terminating end initiateing teardownsequencing diagram; [0139]
FIG. 41 depicts a block diagram of a call flow showing a soft switch processing an REL message tearing down all nodes sequencing diagram; [0140]
FIG. 42 depicts a block diagram of a call flow showing a soft switch processing an RLC message with the terminating end initiating teardown sequencing diagram; [0141]
FIG. 43 depicts a block diagram of a call flow showing a soft switch sending an unallocate message to route server for call teardown sequencing diagram; [0142]
FIG. 44 depicts a block diagram of a call flow showing a soft switch unallocating route nodes sequencing diagram; [0143]
FIG. 45 depicts a block diagram of a call flow showing a a soft switch processing call teardown and deleting call context sequencing diagram; [0144]
FIG. 46 depicts a block diagram of a call flow showing a route server calculating a domestic route sequencing diagram for a voice call on a NAS; [0145]
FIG. 47 depicts a block diagram of a call flow showing a soft switch getting call context from route response sequencing diagram; [0146]
FIG. 48 depicts a block diagram of a call flow showing a soft switch processing an IAM sending the IAM to the terminating network sequencing diagram; [0147]
FIG. 49 depicting a block diagram of a call flow showing calculation of a domestic route for a data call sequencing diagram; [0148]
FIG. 50 depicts a block diagram of a call flow showing a soft switch getting call context from route response sequencing diagram; [0149]
FIG. 51 depicts a block diagram of a call flow showing a soft switch processing an IAM connnecting the data call sequencing diagram; soft switch receiving and acknowledging receipt of a signaling message from an SS7 GW sequencing diagram; [0150]
FIG. 52 depicts a block diagram of a call flow showing a soft switch processing an ACM message including sending an ACM to an originating network sequencing diagram; [0151]
FIG. 53 depicts a block diagram of a call flow showing a soft switch processing an ANM message including sending an ANM to an originating network sequencing diagram; [0152]
FIG. 54 depicts a block diagram of a call flow showing a soft switch processing an RCR message sequencing diagram; [0153]
FIG. 55 depicts a block diagram of a call flow showing a soft switch processing an RLC message sequencing diagram; [0154]
FIG. 56 depicts a block diagram of a call flow showing a soft switch processing an ACM message sending an ACM to the originating network sequencing diagram; [0155]
FIG. 57 depicts a block diagram of a call flow showing a soft switch processing an IAM setting up access servers; [0156]
FIG. 58A depicts a block diagram of the H.323 architecture for a network-based communications system defining four major components, including, terminals, gateways, gatekeepers, and multipoint control units; [0157]
FIG. 58B depicts an exemplary H.323 terminal; [0158]
FIG. 59 shows an example H.323/PSTN Gateway; [0159]
FIG. 60 depicts an example collection of all terminals, gateways, and multipoint control units which can be managed by a single gatekeeper, collectively known as an H.323 Zone; [0160]
FIG. 61 depicts an exemplary MCU of the H.323 architecture; [0161]
FIG. 62 depicts a block diagram showing a soft switch in communication with an access server; [0162]
FIG. 63 depicts a flowchart of an Access Server Side Inbound Call Handling state diagram; [0163]
FIG. 64A depicts a flowchart of an Access Server Side Exception Handling state diagram; [0164]
FIG. 64B further depicts a flowchart of an Access Server Side Exception Handling state diagram; [0165]
FIG. 65 depicts a flowchart of an Access Server Side Release Request Handling state diagram; [0166]
FIG. 66 depicts a flowchart of an Access Server Side TDM Connection Handling state diagram; [0167]
FIG. 67A depicts a flowchart of an Access Server Side Continuity Test Handling state diagram; [0168]
FIG. 67B further depicts a flowchart of an Access Server Side Continuity Test Handling state diagram; [0169]
FIG. 68A depicts a flowchart of an Access Server Side Outbound Call Handling Initiated by Access Server state diagram; [0170]
FIG. 68B further depicts a flowchart of an Access Server Side Outbound Call Handling Initiated by Access Server state diagram; [0171]
FIG. 69 depicts a flowchart of an Access Server Outbound Call Handling Initiated by Soft Switch state diagram; [0172]
FIG. 70A depicts an exemplary diagram of an OOP Class Definition; and [0173]
FIG. 70B depicts an exemplary computer system of the present invention.[0174]
In the figures, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The figure in which an element first appears is indicated by the leftmost digit(s) in the reference number. [0175]
I. High Level Description [0176]
A. Structural Description [0177]
1. Soft Switch Sites [0178]
2. Gateway Sites [0179]
3. Data Network [0180]
4. Signaling Network [0181]
5. Network Event Component [0182]
6. Provisioning Component [0183]
7. Network Management Component [0184]
B. Operational Description [0185]
II. Intermediate Level Description [0186]
A. Structural Description [0187]
1. Soft Switch Site [0188]
a. Soft Switch [0189]
b. SS7 Gateway [0190]
c. Signal Transfer Points (STPs) [0191]
d. Services Control Points (SCPs) [0192]
e. Configuration Server (CS) or Configuration Database (CDB) [0193]
f. Route Server [0194]
g. Regional Network Event Collection Point (RNECP) [0195]
2. Gateway Site [0196]
a. Trunking Gateway (TG) [0197]
b. Access Gateway (AG) [0198]
c. Network Access Server (NAS) [0199]
d. Digital Cross-Connect System (DACS) [0200]
e. Announcement Server (ANS) [0201]
3. Data Network [0202]
a. Routers [0203]
b. Local Area Networks (LANs) and Wide Area Networks (WANs) [0204]
c. Network Protocols [0205]
4. Signaling Network [0206]
a. Signal Transfer Points (STPs) [0207]
b. Service Switching Points (SSPs) [0208]
c. Services Control Points (SCPs) [0209]
5. Provisioning Component and Network Event Component [0210]
a. Data Distributor [0211]
6. Provisioning Component and Network Event Component [0212]
a. Master Network Event Database [0213]
7. Network management component [0214]
B. Operational Description [0215]
III. Specific Implementation Example Embodiments [0216]
A. Structural Description [0217]
1. Soft Switch Site [0218]
a. Soft Switch [0219]
(1) Soft Switch Interfaces [0220]
b. SS7 Gateway [0221]
(1) SS7 Gateway Example Embodiment [0222]
(2) SS7 Gateway-to-Soft Switch Interface [0223]
c. Signal Transfer Points (STPs) [0224]
(1) STP Example Embodiment [0225]
(a) Global Title Translation [0226]
(b) Gateway Screening Software [0227]
(c) Local Number Portability (LNP) [0228]
(d) STP to LAN Interface [0229]
(e) ANSI to ITU Gateway [0230]
d. Services Control Points (SCPs) [0231]
(1) Additional Services Calls [0232]
(2) Project Account Codes [0233]
(3) Basic Toll-Free [0234]
e. Configuration Server (CS) or Configuration Database (CDB) [0235]
f. Route Server [0236]
(1) Route Server Routing Logic [0237]
(2) Route Server Circuit Management [0238]
g. Regional Network Event Collection Point (RNECP) [0239]
(1) Example Mandatory Event Blocks EBs [0240]
(2) Augmenting Event Blocks EBs [0241]
h. Software Object Oriented Programming (OOPs) Class Definitions [0242]
(1) Introduction to Object Oriented Programming (OOP) [0243]
(2) Software Objects in an OOP Environment [0244]
(3) Class Definitions [0245]
(a) Soft Switch Class [0246]
(b) Call Context Class [0247]
(c) Signaling Message Class [0248]
(d) SS7 Gateway Class [0249]
(e) IPDC Message Class [0250]
(f) Call Event Identifier Class [0251]
(g) Configuration Proxy Class [0252]
(h) Route Server Class [0253]
(i) Route Objects Class [0254]
(j) Pool Class [0255]
(k) Circuit Pool Class [0256]
2. Gateway Site [0257]
a. Trunking Gateway (TG) [0258]
(1) Trunking Gateway Interfaces [0259]
b. Access Gateway (AG) [0260]
(1) Access Gateway Interfaces [0261]
c. Network Access Server (NAS) [0262]
(1) Network Access Server Interfaces [0263]
d. Digital Cross-Connect System (DACS) [0264]
e. Announcement Server (ANS) [0265]
3. Data Network [0266]
a. Routers [0267]
b. Local Area Networks (LANs) and Wide Area Networks (WANs) [0268]
c. Network Protocols [0269]
(1) Transmission Control Protocol/Internet Protocol (TCP/IP) [0270]
(2) Internet Protocol (IP)v4 and IPv6 [0271]
(3) Resource Reservation Protocol (RSVP) [0272]
(4) Real-time Transport Protocol (RTP) [0273]
([0274] 5) IP Multi-Casting Protocols
d. Virtual Private Networks (VPNs) [0275]
(1) VPN Protocols [0276]
(a) Point-to-Point Tunneling Protocol (PPTP) [0277]
(b) Layer 2 Forwarding (L2F) Protocol [0278]
(c) Layer 2 Tunneling Protocol (L2TP) [0279]
e. Exemplary Data Networks [0280]
(1) Asynchronous Transfer Mode (ATM) [0281]
(2) Frame Relay [0282]
(3) Internet Protocol (IP) [0283]
4. Signaling Network [0284]
a. Signal Transfer Points (STPs) [0285]
b. Service Switching Points (SSPs) [0286]
c. Services Control Points (SCPs) [0287]
5. Provisioning Component and Network Event Component [0288]
a. Data Distributor [0289]
(1) Data Distributor Interfaces [0290]
6. Provisioning Component and Network Event Component [0291]
a. Master Network Event Database [0292]
(1) MNEDB Interfaces [0293]
(2) Event Block Definitions [0294]
(a) Example Mandatory Event Blocks (EBs) Definitions [0295]
(b) Example Augmenting Event Block (EBs) Definitions [0296]
(3) Example Element Definitions [0297]
(4) Element Definitions [0298]
7. Network management component [0299]
a. Network operations center (NOC) [0300]
b. Simple Network Management Protocol (SNMP) [0301]
c. Network Outage Recovery Scenarios —(1) Complete Gateway Site Outage [0302]
(2) Soft Switch Fail-Over [0303]
(3) Complete Soft Switch Site Outage Scenario [0304]
8. Internet Protocol Device Control (IPDC) Protocol [0305]
a. IPDC Base Protocol [0306]
b. IPDC Control Protocol [0307]
c. IPDC Control Message Codes [0308]
d. A Detailed View of the IPDC Protocol Control Messages [0309]
(1) Startup Messages [0310]
(2) Protocol Error Messages [0311]
(3) System Configuration Messages [0312]
(4) Telephone Company Interface Configuration Messages [0313]
(5) Soft Switch Configuration Messages [0314]
(6) Maintenance-Status Messages [0315]
(7) Continuity Test Messages [0316]
(8) Keepalive Test Messages [0317]
(9) LAN Test Messages [0318]
(10) Tone Function Messages [0319]
(11) Example Source Port Types [0320]
(12) Example Internal Resource Types [0321]
(13) Example Destination Port Types [0322]
(14) Call Control Messages [0323]
(15) Example Port Definitions [0324]
(16) Call Clearing Messages [0325]
(17) Event Notification Messages [0326]
(18) Tunneled Signaling Messages [0327]
e. Control Message Parameters [0328]
f. A Detailed View of the Flow of Control Messages [0329]
(1) Startup Flow [0330]
(2) Module Status Notification Flow [0331]
(3) Line Status Notification Flow [0332]
(4) Blocking of Channels Flow [0333]
(5) Unblocking of Channels Flow [0334]
(6) Keepalive Test Flow [0335]
(7) Reset Request Flow [0336]
g. Call Flows [0337]
(1) Data Services [0338]
(a) Inbound Data Call via SS7 Signaling Flow [0339]
(b) Inbound Data Call via Access Server Signaling Flow [0340]
(c) Inbound Data Call via SS7 Signaling (with call-back) [0341]
(d) Inbound Data Call (with loopback continuity testing) Flow [0342]
(e) Outbound Data Call Flow via SS7 Signaling [0343]
(f) Outbound Data Call Flow via Access Server Signaling [0344]
(g) Outbound Data Call Flow Initiated from the Access Server with continuity testing [0345]
(2) TDM Switching Setup Connection Flow [0346]
(a) Basic TDM Interaction Sequence [0347]
(b) Routing of calls to Appropriate Access Server using TDM connections Flow [0348]
(3) Voice Services [0349]
(a) Voice over Packet Services Call Flow (Inbound SS7 signaling, Outbound access server signaling, Soft Switch managed RTP ports) [0350]
(b) Voice over Packet Call Flow (Inbound access server signaling, Outbound access server signaling, Soft switch managed RTP ports) [0351]
(c) Voice over Packet Call Flow (Inbound SS7 signaling, outbound SS7 signaling, IP network with access server managed RTP ports) [0352]
(d) Unattended Call Transfers Call Flow [0353]
(e) Attended Call Transfer Call Flow [0354]
(f) Call termination with a message announcement Call Flow [0355]
(g) Wiretap [0356]
B. Operational Description [0357]
1. Voice Call originating and terminating via SS7 signaling on a Trunking Gateway [0358]
a. Voice Call on a TG Sequence Diagrams of Component Intercommunication [0359]
2. Data Call originating on an SS7 trunk on a Trunking Gateway [0360]
3. Voice Call originating on an SS7 trunk on a Trunking Gateway and terminating via access server signaling on an Access Gateway [0361]
4. Voice Call originating on an SS7 trunk on a Trunking Gateway and terminating on an Announcement Server [0362]
5. Voice Call originating on an SS7 trunk on a Network Access Server and terminating on a Trunking Gateway via SS7 signaling [0363]
a. Voice Call on a NAS Sequence Diagrams of Component Intercommunication [0364]
6 Voice Call originating on an SS7 trunk on a NAS and terminating via Access Server Signaling on an Access Gateway [0365]
7. Data Call originating on an SS7 trunk and terminating on a NAS [0366]
a. Data Call on a NAS Sequence Diagrams of Component intercommunication [0367]
8. Data Call on NAS with Callback outbound reorigination [0368]
9. Voice Call originating on Access Server dedicated line on an Access Gateway and terminating on an Access Server dedicated line on an Access Gateway [0369]
10. Voice Call originating on Access Server signaled private line on an Access Gateway and terminating on SS7 signaled trunks on a Trunking Gateway [0370]
11. Data Call on an Access Gateway [0371]
12. Outbound Data Call from a NAS via Access Server signaling from an Access Gateway [0372]
13. Voice Services [0373]
a. Private Voice Network (PVN) Service [0374]
b. 1+ Long Distance Service [0375]
(1) Project Account Codes (PAC) [0376]
(a) PAC Variations [0377]
(2) Class of Service Restrictions (COSR) [0378]
(3) Origination and Termination [0379]
(4) Call Rating [0380]
(5) Multiple Service T-1 [0381]
(6) Monthly Recurring Charges (MRCs) [0382]
(7) PVN Private Dialing Plan [0383]
(8) Three-Way Conferencing [0384]
(9) Network Hold with Message Delivery [0385]
c. 8XX Toll Free Services [0386]
(1) Enhanced Routing Features [0387]
(2) Info-Digit Blocking [0388]
(3) Toll-Free Number Portability (TFNP) [0389]
(4) Multiple-Server T-1 [0390]
(5) Call Rating [0391]
(6) Project Accounting Codes [0392]
(7) Toll-Free Directory Listings [0393]
(8) Menu Routing [0394]
(9) Network ACD [0395]
(10) Network Transfer (TBX) [0396]
(11) Quota Routing [0397]
(12) Toll-Free Valet (Call Park) [0398]
d. Operator Services [0399]
(1) Domestic Operator Services [0400]
(a) Operator Services Features [0401]
(2) International Operator Services [0402]
e. Calling Card Services [0403]
(1) Calling Card Features [0404]
(2) Call Rating [0405]
f. One-Number Services [0406]
(1) One Number Features [0407]
g. Debit Card/Credit Card Call Services [0408]
h. Local Services [0409]
(1) Local Voice/Dial Tone (LV/DT) [0410]
(2) Call Handling Features [0411]
(a) Line Hunting [0412]
(b) Call Forward Busy [0413]
(c) Call Forwarding Don't Answer [0414]
(d) Call Forward Variable [0415]
(e) Call Hold [0416]
(f) Three-Way Calling [0417]
(g) Call Transfer [0418]
(h) Call Waiting/Cancel Call Waiting [0419]
(i) Extension or Station-to-Station Calling [0420]
(j) Direct Connect Hotline/Ring Down Line [0421]
(k) Message Waiting Indicator [0422]
(l) Distinctive Ringing [0423]
(m) Six-Way Conference Calling [0424]
(n) Speed Calling [0425]
(o) Selective Call Rejection [0426]
(p) Remote Activation of Call Forward Variable [0427]
(3) Enhanced Services [0428]
(a) Remote Call Forward (RCF) [0429]
(b) Voice Messaging Services [0430]
(c) Integrated Voice Messaging [0431]
(d) Stand-alone Voice Messaging [0432]
(4) Class Services [0433]
(5) Class of Service Restrictions [0434]
(b) Local Voice/Local Calling (LV/LC) [0435]
i. Conferencing Services [0436]
(1) Audio Conferencing [0437]
(a) Audio conferencing features [0438]
(2) Video Conferencing [0439]
14. Data Services [0440]
a. Internet Hosting [0441]
b. Managed Modem Services [0442]
c. Collocation Services [0443]
d. IP network Services [0444]
e. Legacy Protocol Services—Systems Network Architecture (SNA) [0445]
f. Permanent Virtual Circuits [0446]
15. Additional Products and Services [0447]
IV. Definitions [0448]
V. Conclusion [0449]
I. High Level Description [0450]
This section provides a high-level description of the voice over IP network architecture according to the present invention. In particular, a structural implementation of the voice over IP (VOIP) network architecture is described at a high-level. Also, a functional implementation for this structure is described at a high-level. This structural implementation is described herein for illustrative purposes, and is not limiting. In particular, the process described in this section can be achieved using any number of structural implementations, one of which is described in this section. The details of such structural implementations will be apparent to persons skilled in the relevant arts based on the teachings contained herein. [0451]
A. Structural Description [0452]
FIG. 1 is a block diagram [0453] 100 illustrating the components of the VOIP architecture at a high-level. FIG. 1 includes soft switch sites 104, 106, gateway sites 108, 110, data network 112, signaling network 114, network event component 116, provisioning component 117 and network management component 118.
Included in FIG. 1 are calling parties [0454] 102, 122 and called parties 120, 124. Calling parties 102, 122 are homed to gateway site 108. Calling parties 102, 122 are homed to gateway site 108. Called parties 120, 124 are homed to gateway site 110. Calling party 102 can be connected to gateway site 108 via trunks from carrier facility 126 to gateway site 108. Similarly, called party 120 can be connected to gateway site 110 via trunks from carrier facility 130 to gateway site 110. Calling party 122 can be connected to gateway site 108 via a private line or dedicated access line (DAL) from customer facility 128 to gateway site 108. Similarly, called party 124 can be connected to gateway site 110 via a private line or a DAL from customer facility 132 to gateway site 110.
Calling party [0455] 102 and called party 120 are off-network, meaning that they are connected to gateway sites 108, 110 via the Public Switched Telephone Network (PSTN) facilities. Calling party 122 and called party 124 are on-network, meaning that connect to gateway sites 108, 110 as direct customers.
1. Soft Switch Sites [0456]
Soft switch sites [0457] 104, 106 provide the core call processing for the voice network architecture. Soft switch sites 104, 106 can process multiple types of calls. First, soft switch sites 104, 106 can process calls originating from or terminating at on-network customer facilities 128, 132. Second, soft switch sites 104, 106 can process calls originating from or terminating at off-network customer facilities 126, 130.
Soft switch sites [0458] 104, 106 receive signaling messages from and send signaling messages to signaling network 114. For example, these signaling messages can include SS7, primary rate interface (PRI) and in-band signaling messages. Soft switch sites 104, 106 process these signaling messages for the purpose of establishing new calls from calling parties 102, 122 through data network 112 to called parties 120, 124. Soft switch sites 104, 106 also process these signaling messages for the purpose of tearing down existing calls established between calling parties 102, 122 and called parties 120, 124 (through data network 112).
Calls can be transmitted between any combination of on-network and off-network callers. [0459]
In one embodiment, signaling messages for a call which either originates from an off-network calling party [0460] 102, or terminates to an off-network called party 120, can be carried over out-of-band signaling network 114 from the PSTN to soft switches 104, 106.
In another embodiment, signaling messages for a call which either originates from an on-network calling party [0461] 122, or terminates to on-network called party 124, can be carried in-band over data network 112 or over a separate data network to soft switch sites 104, 106, rather than through signaling network 114.
Soft switch sites [0462] 104, 106 can be collocated or geographically diverse. Soft switch sites 104, 106 can also be connected by redundant connections to data network 112 to enable communication between soft switches 104, 106.
Soft switch sites [0463] 104, 106 use other voice network components to assist with the processing of calls. For example, gateway sites 108, 110 provide the means to originate and terminate calls on the PSTN. In a preferred embodiment, soft switch sites 104, 106 use the Internet Protocol Device Control (IPDC) protocol to control network access devices known as media gateways in gateway sites 108, 110, and to request, for example, the set-up and tear-down of calls. The IPDC protocol is described below with reference to Tables 144-185. Alternatively, any protocol understood by those skilled in the art can be used to control gateway sites 108, 110. One example of an alternative protocol is the Network Access Server (NAS) Messaging Interface (NMI) Protocol, discussed in U.S. patent application entitled “System and Method for Bypassing Data from Egress Facilities”, filed concurrently herewith, Attorney Docket No. 1757.0060000, the contents of which are incorporated herein by reference in their entirety. Another example of a protocol is the Media Gateway Control Protocol (MGCP) from the Internet Engineering Task Force (IETF).
Soft switch sites [0464] 104, 106 can include other network components such as a soft switch, which more recently can also be known as a media gateway controller, or other network devices.
2. Gateway Sites [0465]
Gateway sites [0466] 108, 110 provide the means to originate and terminate calls between calling parties 102, 122 and called parties 120, 124 through data network 112. For example, calling party 122 can originate a call terminated to off-network called party 120, which is homed to gateway site 110 via carrier facility 130.
Gateway sites [0467] 108, 110 can include network access devices to provide access to network resources. An example of a network access device is an access server which is more recently commonly known as a media gateway. These devices can include trunking gateways, access gateways and network access servers. Gateway sites 108, 110 provide for transmission of, for example, both voice and data traffic through data network 112.
Gateway sites [0468] 108, 110 are controlled or managed by one or more soft switch sites 104, 106. As noted, soft switch sites 104, 106 can communicate with gateway sites 108, 110 via the IPDC, NMI, MGCP, or alternative protocols.
Gateway sites [0469] 108, 110 can provide trunk interfaces to other telecommunication carriers via carrier facilities 126, 130 for the handling of voice calls. The trunk interfaces can also be used for the termination of dial-up modem data calls. Gateway sites 108, 110 can also provide private lines and dedicated access lines, such as T1 or ISDN PRI facilities, to customer facilities 128, 132. Examples of customer facilities 128, 132 are customer premises equipment (CPE) such as, for example, a private branch exchange (PBX).
Gateway sites [0470] 108, 110 can be collocated or geographically diverse from one another or from other network elements (e.g. soft switch sites 104, 106). Gateway sites 108, 110 can also be connected by redundant connections to data network 112 to enable communication with and management by soft switches 104, 106.
3. Data Network [0471]
Data network [0472] 112 connects one or more soft switch sites 104, 106 to one or more gateway sites 108, 110. Data Network 112 can provide for routing of data through routing devices to destination sites on data network 112. For example, data network 112 can provide for routing of internet protocol (IP) packets for transmission of voice and data traffic from gateway site 108 to gateway site 110. Data Network 112 represents any art-recognized data network. One well-known data network is the global Internet. Other examples include a private intranet, a packet-switched network, a frame relay network, and an asynchronous transfer mode (ATM) network.
4. Signaling Network [0473]
Signaling network [0474] 114 is an out-of-band signaling network providing for transmission of signaling messages between the PSTN and soft switch sites 104, 106. For example, signaling network 114 can use Common Channel Interoffice Signaling (CCIS), which is a network architecture for out-of-band signaling. A popular version of CCIS signaling is Signaling System 7 (SS7). SS7 is an internationally recognized system optimized for use in digital telecommunications networks.
5. Network Event Component [0475]
Network event component [0476] 116 provides for collection of call events recorded at soft switch sites 104, 106. Call event records can be used, for example, for fraud detection and prevention, traffic reporting and billing.
6. Provisioning Component [0477]
Provisioning component [0478] 117 provides several functions. First, provisioning component 117 receives provisioning requests from upstream operational support services (OSS) systems, for such items as order-entry, customer service, and customer profile changes. Second, provisioning component 117 distributes provisioning data to appropriate network elements. Third provisioning component 117 maintains data synchronization, consistency, and integrity across multiple soft switch sites 104, 106.
7. Network Management Component [0479]
Network management component [0480] 118 can include a network operations center (NOC) for centralized network management. Each network element (NE) of block diagram 100 can generate simple network management protocol (SNMP) events or alerts. The NOC uses the events generated by a NE to determine the health of the network, and to perform other network management functions.
B. Operational Description [0481]
The following operational flows describe an exemplary high level call scenario for soft switch sites [0482] 104, 106 and is intended to demonstrate at a high architectural level how soft switch sites 104, 106 process calls. The operational flow of the present invention is not to be viewed as limited to this exemplary illustration.
As an illustration, FIG. 22A depicts a simple operational call flow chart describing how soft switch sites [0483] 104, 106 can process a long distance call, also known as a 1+ call. The operational call flow of FIG. 22A begins with step 2202, in which a soft switch site receives an incoming signaling message. The call starts by soft switch site 104 receiving an incoming signaling message from carrier facility 126 via signaling network 114, indicating an incoming call from calling party 102.
In step [0484] 2204, the soft switch site determines the type of call by performing initial digit analysis. Based upon the information in the signaling message, the soft switch site 104 analyzes the initial digit of the dialed number of the call and determines that it is a 1+ call.
In step [0485] 2222, soft switch site 104 can select a route termination based on the dialed number (i.e., the number of called party 120 dialed by calling party 102) using least cost routing. This route termination can involve termination off data network 112 or off onto another data network. Soft switch site 104 can then communicate with soft switch site 106 to allocate a terminating circuit in gateway site 110 for this call.
In step [0486] 2224, soft switch site 104 can indicate connections to be made to complete the call. Soft switch site 104 or soft switch site 106 can return a termination that indicates the connections that must be made to connect the call.
In step [0487] 2226, soft switch sites 104, 106 instruct the gateway sites to make connections to set up the call. Soft switch sites 104, 106 can send messages through data network 112 (e.g. using IPDC protocol commands) to gateway sites 108, 110, to instruct the gateway sites to make the necessary connections for setting up the call origination from calling party 102, the call termination to called party 120, and the connection between origination and termination.
In step [0488] 2228, soft switch sites 104, 106 generate and send network events to a repository. Soft switch sites 104, 106 can generate and send network events to network event component 116 that are used, for example, in detecting and preventing fraud, and in performing billing.
In step [0489] 2230, network management component 118 monitors the telecommunications network 100. All network elements create network management events such as SNMP protocol alerts or events. Network management component 118 can monitor SNMP events to enable management of network resources.
FIG. 22B details a more complex operational call flow describing how soft switch sites [0490] 104, 106 process a long distance call. FIG. 22B inserts steps 2206, 2208 and 2220 between steps 2204 and 2222 of FIG. 22A.
The operational call flow of FIG. 22B begins with step [0491] 2202, in which a soft switch site receives an incoming signaling message. The call starts by soft switch site 104 receiving an incoming signaling message from carrier facility 126 via signaling network 114, indicating an incoming call from calling party 102.
In step [0492] 2204, the soft switch site determines the-type of call by performing initial digit analysis. Based upon the information in the signaling message, the soft switch site 104 analyzes the initial digit of the dialed number of the call and determines that it is a 1+ call.
In step [0493] 2206, the soft switch site queries a customer profile database to retrieve the originating trigger plan associated with the calling customer. With a 1+ type of call, the logic within the soft switch knows to query the customer profile database within soft switch site 104 to retrieve the originating trigger plan for the calling party. The step 2206 query can be made using the calling party number. The customer profile lookup is performed using as the lookup key, the originating number, i.e., the number of calling party 102, provided in the signaling message from signaling network 114.
In step [0494] 2208, the lookup returns subscription information. For example, the customer profile can require entry of an account code. In this example, the customer profile lookup can return an indication that the customer, i.e., calling party 102, has subscribed to an account code verification feature. A class of service restriction can also be enforced, but this will not be known until account code verification identifies an associated account code.
In step [0495] 2220, soft switch site 104 completes customer service processing and prepares to terminate the call. At this point, soft switch site 104 has finished executing all customer service logic and has a 10-digit dialed number that must be terminated.
In step [0496] 2222, soft switch site 104 can select a route termination based on the dialed number (i.e., the number of called party 120 dialed by calling party 102) using least cost routing. This route termination can involve termination off data network 112 or off onto another data network. Soft switch site 104 can then communicate with soft switch site 106 to allocate a terminating circuit in gateway site 110 for this call.
In step [0497] 2224, soft switch site 104 can indicate connections to be made to complete the call. Soft switch site 104 or soft switch site 106 can return a termination that indicates the connections that must be made to connect the call.
In step [0498] 2226, soft switch sites 104, 106 instruct the gateway sites to make connections to set up the call. Soft switch sites 104, 106 can send messages through data network 112 (e.g. using IPDC protocol commands) to gateway sites 108, 110, to instruct the gateway sites to make the necessary connections for setting up the call origination from calling party 102, the call termination to called party 120, and the connection between origination and termination.
In step [0499] 2228, soft switch sites 104, 106 generate and send network events to a repository. Soft switch sites 104, 106 can generate and send network events to network event component 116 that are used, for example, in detecting and preventing fraud, and in performing billing.
In step [0500] 2230, network management component 118 monitors the telecommunications network 100. All network elements create network management events such as SNMP protocol alerts or events. Network management component 118 can monitor SNMP events to enable management of network resources.
FIG. 22C details an even more complex operational call flow describing how soft switch sites [0501] 104, 106 can be used to process a long distance call using project account codes and class of service restrictions. FIG. 22C inserts steps 2210 through 2218 between steps 2208 and 2220 of FIG. 22B.
The operational call flow of FIG. 22C begins with step [0502] 2202, in which a soft switch site receives an incoming signaling message. The call starts by soft switch site 104 receiving an incoming signaling message from carrier facility 126 via signaling network 114, indicating an incoming call from calling party 102.
In step [0503] 2204, the soft switch site determines the type of call by performing initial digit analysis. Based upon the information in the signaling message, the soft switch site 104 analyzes the initial digit of the dialed number of the call and determines that it is a 1+ call.
In step [0504] 2206, the soft switch site queries a customer profile database to retrieve the originating trigger plan associated with the calling customer. With a 1+ type of call, the logic within the soft switch knows to query the customer profile database within soft switch site 104 to retrieve the originating trigger plan for the calling party. The step 2206 query can be made using the calling party number. The customer profile lookup is performed using as the lookup key, the originating number, i.e., the number of calling party 102, provided in the signaling message from signaling network 114.
In step [0505] 2208, the lookup returns subscription information. For example, the customer profile can require entry of an account code. In this example, the customer profile lookup can return an indication that the customer, i.e., calling party 102, has subscribed to an account code verification feature. A class of service restriction can also be enforced, but this will not be known until account code verification identifies an associated account code.
In step [0506] 2210, soft switch site 104 instructs gateway site 108 to collect account codes. Using the information in the customer profile, soft switch site 104 can use the IPDC protocol to instruct gateway site 108 to collect a specified number of digits from calling party 102.
In step [0507] 2212, soft switch site 104 determines how to process received digits. Assuming gateway site 108 collects the correct number of digits, soft switch site 104 can use the customer profile to determine how to process the received digits. For account code verification, the customer profile can specify whether the account code needs to be validated.
In step [0508] 2214, soft switch site 104 verifies the validity of the received digits. If the account code settings in the customer profile specify that the account code must be verified and forced to meet certain criteria, soft switch site 104 performs two functions. Because “verify” was specified, soft switch site 104 queries a database to verify that the collected digits meet such criteria, i.e., that the collected digits are valid. Because “forced” was specified, soft switch site 104 also forces the calling customer to re-enter the digits if the digits were not valid.
In step [0509] 2216, verification can result in the need to enforce a restriction, such as a class of service (COS) restriction (COSR). In this example, soft switch site 104 can verify that the code is valid, but that it requires, for example, that an intrastate COSR should be enforced. This means that the call is required to be an intrastate call to be valid. The class of service restriction logic can be performed within soft switch site 104 using, for example, pre-loaded local access and transport areas (LATAs) and state tables.
If project account codes (PACs) are not used, class of service (COS) restrictions can be applied based on originating ANI or ingress trunk group. [0510]
In step [0511] 2218, soft switch 104 allows the call to proceed if the class of service requested is permitted. For example, if the LATA and state tables show that the LATAs of originating party (i.e., calling party 102) and terminating party (i.e. called party 120), must be, and are, in the same state, then the call can be allowed to proceed.
In step [0512] 2220, soft switch site 104 completes customer service processing and prepares to terminate the call. At this point, soft switch site 104 has finished executing all customer service logic and has a 10-digit dialed number that must be terminated.
In step [0513] 2222, soft switch site 104 can select a route termination based on the dialed number (i.e., the number of called party 120 dialed by calling party 102) using least cost routing. This route termination can involve termination off data network 112 or off onto another data network. Soft switch site 104 can then communicate with soft switch site 106 to allocate a terminating circuit in gateway site 110 for this call.
In step [0514] 2224, soft switch site 104 can indicate connections to be made to complete the call. Soft switch site 104 or soft switch site 106 can return a termination that indicates the connections that must be made to connect the call.
In step [0515] 2226, soft switch sites 104, 106 instruct the gateway sites to make connections to set up the call. Soft switch sites 104, 106 can send messages through data network 112 (e.g. using IPDC protocol commands) to gateway sites 108, 110, to instruct the gateway sites to make the necessary connections for setting up the call origination from calling party 102, the call termination to called party 120, and the connection between origination and termination.
In step [0516] 2228, soft switch sites 104, 106 generate and send network events to a repository. Soft switch sites 104, 106 can generate and send network events to network event component 116 that are used, for example, in detecting and preventing fraud, and in performing billing.
In step [0517] 2230, network management component 118 monitors the telecommunications network 100. All network elements create network management events such as SNMP protocol alerts or events. Network management component 118 can monitor SNMP events to enable management of network resources.
The intermediate level description and specific implementation example embodiments sections, below, will describe additional details of operation of the invention. For example, how soft-switch site [0518] 104 performs initial digit analysis to identify the type of call and how to process the call will be discussed further. The sections also provide details regarding how soft switch sites 104, 106 interact with the other components of the voice network architecture.
II. Intermediate Level Description [0519]
This section provides an intermediate level description of the VOIP network architecture according to the present invention. A structural implementation of the VOIP network architecture is described at an intermediate level. Also, a functional implementation for this structure is described at an intermediate level. This structural implementation is described herein for illustrative purposes, and is not limiting. In particular, the process described in this section can be achieved using any number of structural implementations, one of which is described in this section. The details of such structural implementations will be apparent to persons skilled in the relevant arts based on the teachings contained herein. [0520]
A. Structural Description [0521]
FIG. 2A is a block diagram further illustrating the components of VOIP architecture [0522] 100 at an intermediate level of detail. FIG. 2A depicts telecommunications system 200. Telecommunications system 200 includes soft switch site 104, gateway sites 108, 110, data network 112, signaling network 114, network event component 116, provisioning component 117 and network management component 118. Included in FIG. 2A are calling parties 102, 122 and called parties 120, 124.
Soft switch site [0523] 104 includes soft switch 204, SS7 gateways 208, 210, service control point (SCP) 214, configuration server/configuration database (CDB) 206, route server 212, signal transfer points (STPs) 250, 252, and regional network event collection point (RNECP) 224. Table 1 below describes the functions of these network elements in detail.
Soft switch component Description
soft switch (SS) Soft switches are call control components
responsible for processing of signaling
messages, execution of call logic and control
of gateway site access devices.
SS7 gateways (SS7 GW) SS7 gateways provide an interface between the
SS7 signaling network and the soft switch.
service switching Service switching points are the portions of
points (SSP) backbone switches providing SS7 functions.
For example, any switch in the PSTN is an SSP
if it provides SS7 functions. A soft switch is an
signal transfer Signal transfer points route signaling messages
point (STP) from originating service switching points
(SSPs) to destination SSPs.
service control Service control points provide number
translations for toll free services and validation
point (SCP) of project account codes for PAC services.
configuration Configuration servers are servers managing
server/configuration customer profiles, voice network topologies
database (CDB) and configuration data. The configuration
database is used for storage and retrieval of
route server (RS) Route servers are responsible for selection of
least cost routes through the network and
allocation of network ports.
regional network Route servers are responsible for selection of
event collection least cost routes through the network and
point (RNECP) allocation of network ports. regional network
event collection points are points in the
network that collect call event data.
Gateway site [0524] 108 includes trunking gateway (TG) 232, access gateway (AG) 238, network access server (NAS) 228, digital cross-connect system (DACS) 242 and announcement server (ANS) 246. TG 232, AG 238, and NAS 228 are collectively known as access server 254. Similarly, gateway site 110 includes TG 234, AG 240, NAS 230, DACS 244 and ANS 248. TG 234, AG 240, and NAS 230 are collectively known as access server 256. Gateway sites 108, 110 provide trunk, private line and dedicated access line connectivity to the PSTN. Table 2 below describes the functions of these network elements in detail.
Gateway site component Description
trunking gateway (TG) A trunking gateway provides full-duplex PSTN
to IP conversion for co-carrier and feature
group D (FG-D) trunks.
access gateway (AG) An access gateway provides full-duplex PSTN
to IP conversion for ISDN-PRI and T1 digital
dedicated access lines (DALs).
network access A network access server provides modem
server (NAS) access to an IP network. A digital access and
cross-connect system is a digital switching
digital access and cross- system used for the routing and switching of
connect system (DACS) T-1 lines and DS-0 circuits of lines, among
multiple T-1 ports.
announcement An announcement server provides a network
server (ANS) with PSTN terminating announcements.
Data network [0525] 112 provides the network bandwidth over which calls can be connected through the telecommunications system. Data network 112 can be, for example, a packet switched data network including network routers for routing traffic through the network.
Signaling network [0526] 114 includes signal transfer points (STPs) 216, 218 and signaling control points (SCPs) associated with each network node. Table 3 below describes the functions of these network elements in detail.
signal transfer Signal transfer points route signaling messages from
points (STPs) originating service switching points (SSPs) to
destination SSPs.
service control Service control point provide number translations
point (SCP) for Toll Free services and validation of project account
codes (PAC) for PAC services.
service switching Service switching points are the portions of backbone
point (SSPs) switches providing SS7 functions. For example, any
switch in the PSTN is an SSP if it provides SS7
functions. A soft switch is an SSP.
Network management component [0527] 118 includes the means to manage a network. Network management component 118 gathers events and alarms related to network events. For example, event logs can be centrally managed from a network operations center (NOC). Alerts and events can be communicated to the NOC via the simple network management protocol (SNMP)). Table 4 below describes the functions of these network elements in detail.
network operations Network operations center is a centralized
center (NOC) location for gathering network management
events and for managing various network
elements via the SNMP protocol.
simple network Simple network management protocol provides
management protocol site filtering of element alarms and messages
(SNMP) before forwarding them to the NOC.
Network event component [0528] 116 includes master network event database (MNEDB) 226. Table 5A below describes the functions of this network element in detail.
master network event database Master network event database is a centralized
(MNEDB) server/database that collects call event records
from regional network event collection points (RNECPs).
It serves as a depository for the event records.
Provisioning component [0529] 117 includes data distributor (DD) 222. Table SB below describes the functions of this network element in detail.
Provisioning component Description
data distributor (DD) The data distributor distributes service requests
and data from upstream Operational Support
Systems (OSS) to network elements. It
maintains synchronization of redundant
B. Operational Description [0530]
The following operational flow describes an exemplary intermediate level call scenario intended to demonstrate at an intermediate architectural level how call processing is handled. The operational flow of the present invention is not to be viewed as limited to this exemplary illustration. [0531]
FIG. 2B depicts an exemplary call flow [0532] 258. FIG. 2B illustrates interaction between a trunking gateway, a soft switch, a configuration server and a route server in order to connect a call through telecommunications network 200.
FIG. 2B details a call flow from TG [0533] 232 of gateway site 108, controlled by soft switch site 104, to TG 234 of gateway site 110, controlled by soft switch site 106. (Soft switch site 106 is illustrated in FIGS. 1 and 3.) Soft switch site 106, including soft switch 304, route server 314, and configuration server 312, is further described below in the Specific Example Embodiments section, with reference to FIG. 3.
Included in call flow [0534] 258 is a description of how soft switch 204 can process a 1+ long distance call that uses project account codes (PACs) with class of service (COS) restrictions. Call flow 258 also assumes that the origination and termination for the call uses SS7 signaling, i.e., that the call comes into network 200 via trunks from carrier facilities 126,130, to trunking gateways 232, 234.
Exemplary call flow [0535] 258 begins with step 259. In step 259, soft switch 204 receives an incoming IAM signaling message from an SS7 GW 208, signaling an incoming call from calling party 102 on carrier facility 126 of a co-carrier.
In step [0536] 260, soft switch 204 sends IPDC commands to trunking gateway 232 to set up a connection (e.g. a DS0 or DS1 circuit) between carrier facility 126 and TG 232 described in the received IAM signaling message. In step 262, trunking gateway 232 sends an acknowledgement message to soft switch 204.
Based upon the information in the LAM message, soft switch [0537] 204 performs initial digit analysis on the dialed number, i.e., the number of called party 120, and determines that the incoming call is a 1+ call.
In step [0538] 263, application program logic within soft switch 204 determines that, with this type of call, i.e., a 1+ call, soft switch 204 should query a customer profile database within configuration server 206, to retrieve the originating customer trigger plan 290 for calling party 102.
The customer profile lookup is performed in configuration server [0539] 206 using the originating automatic number identification (ANI) of calling party 102 as the lookup key.
In step [0540] 264 the customer profile lookup returns to soft switch 204 an indication that the calling party 102 has subscribed to project account codes (PAC). Examples of PACs include billing codes. They provide a mechanism for a network customer, such as a law firm, to keep an accounting of which of their clients to bill. Example call flow 258 will also perform a class of service (COS) restriction, but this will not be known by soft switch 204 until account code verification identifies an associated account code requiring the COS restriction. Alternatively, the customer profile information can reside in route server 212, enabling route server 212 to perform the functions of configuration server 206, in addition to its own functions.
In step [0541] 267, using the information in the customer profile (i.e., customer trigger plans 290) of configuration server 206, soft switch 204 uses the IPDC protocol to instruct trunking gateway 232 to collect the specified number of digits, representing the project account code, from calling party 102.
In step [0542] 268, the digits are sent from trunking gateway 232 to soft switch 204. Assuming that trunking gateway 232 collected the correct number of digits, soft switch 204 uses the customer profile of configuration server 206 to determine how to process the received digits. For project account codes (PACs), the customer profile in configuration server 206 specifies whether the project account code needs to be validated.
If the project account code settings in the customer profile of configuration server [0543] 206 specify that the project account code is “verified and forced,” then soft switch 204, in step 265, can query SCP 214 with the collected digits to verify that they are valid. Table 129 below provides alternative PAC settings.
In step [0544] 266, SCP 214 returns an indication that the project account code is valid, and it requires that an intrastate class of service (COS) restriction should be enforced. The class of service (COS) restriction logic can be performed within soft switch 204, using pre-loaded LATA and state tables from configuration server 206.
If a PAC is not used, the COS restriction can be applied based on ANI or ingress trunk group. [0545]
If the LATA and state tables from configuration server [0546] 206 show that the originating LATA (i.e., the LATA of calling party 102) and the terminating LATA (i.e., the LATA of called party 120) are in the same state, then the call is allowed to proceed.
At this point, soft switch [0547] 204 has finished executing all customer service logic and has a 10-digit DDD number (i.e., the phone number of called party 120), that must be terminated.
In step [0548] 269, soft switch 204 queries route server 212 to receive a call route and to allocate circuits to connect the call. Route server 212 is responsible for using the DDD number to select a least cost route through data network 112, and allocating a terminating circuit for this call.
Additional information on how soft switch [0549] 204 interacts with route server 212 and terminating soft switch 304 is described in the Specific Implementation Example Embodiments Section below, in the section entitled Route Server.
In step [0550] 270, route server 212 returns a route that indicates the connections that soft switch 204 must make to connect the call.
In step [0551] 274, soft switch 204 communicates with soft switch 304 to allocate ports in trunking gateway 234 of gateway site 110, for termination of the call.
Soft switch [0552] 304 is located in a central soft switch site 106. In step 276, soft switch 304 queries port status 298 of route server 314 to identify available ports in trunking gateway 234. In step 278, route server 314 returns an available port to soft switch 304. In steps 280 and 282, soft switch 304 communicates with trunking gateway 234 to allocate a port for termination of the call to called party 120.
In step [0553] 284, soft switch 304 communicates with soft switch 204 to indicate terminating ports have been allocated.
In steps [0554] 286 and 288, soft switch 204 communicates with trunking gateway 232 in order to notify trunking gateway 232 to set up an RTP session (i.e. an RTP over UDP over IP session) with trunking gateway 234 and to permit call traffic to be passed over data network 112.
The Specific Implementation Example Embodiments Section, in the next section, describes additional information about, for example, how soft switch [0555] 204 performs initial digit analysis to identify the type of call, and how to process the call. The next section also describes how soft switch 204 interacts with other components of the voice network architecture 200 in transmitting the call.
III. Specific Implementation Example Embodiments [0556]
Various embodiments related to structures, and operations between these structures described above are presented in this section (and its subsections). These embodiments are described herein for purposes of illustration, and not limitation. The invention is not limited to these embodiments. Alternate embodiments (including equivalents, extensions, variations, deviations, etc., of the embodiments described herein) will be apparent to persons skilled in the relevant arts based on the teachings contained herein. The invention is intended and adapted to include such alternate embodiments. [0557]
Specifically, this section provides a detailed description of the VOIP network architecture according to the present invention. A structural implementation of the (VOIP) network architecture is described at a low-level. Also, a functional implementation for this structure is described at a low-level. [0558]
A. Structural Description [0559]
A more detailed structural description of telecommunications network [0560] 200 will now be described.
1. Soft Switch Site [0561]
FIG. 3 is a block diagram illustrating a more detailed implementation of telecommunications network [0562] 200. Specifically, FIG. 3 illustrates telecommunications network 300 containing three geographically diverse soft switch sites. These soft switch sites include western soft switch site 104, central soft switch 106, and eastern soft switch 302.
Telecommunications network [0563] 300 also includes a plurality of gateway sites that may be collocated or geographically diverse. These gateway sites include gateway sites 108 a, 108 b, 110 a and 110 b.
Data network [0564] 112 can route both signaling and transport traffic between the regional soft switch sites and regional gateway sites. For example, data network 112 can be used to route traffic between western soft switch site 104 and gateway site 110 a. Signaling and transport traffic can also be segregated and sent over separate data networks. As those skilled in the art will recognize, data network 112 can be used to establish a data or voice connection among any of the aforementioned gateway sites 108 a, 108 b, 110 a and 110 b under the control of any of the aforementioned soft switch sites 104, 106 and 302.
Western soft switch site [0565] 104 includes soft switch 204 a, soft switch 204 b, and soft switch 204 c. Soft switches 204 a, 204 b, 204 c can be collocated or geographically diverse. Soft switches 204 a, 204 b, 204 c provide the features of redundancy and high availability.
Failover mechanisms are enabled via this architecture, since the soft switches can act as one big switch. Soft switches [0566] 204 a, 204 b, 204 c can intercommunicate via the inter soft switch communication protocol, permitting access servers to reconnect from one soft switch to another.
Western soft switch site [0567] 104 includes SS7 gateway (GW) 208, configuration server/configuration database (CS/CDB) 206 a and route server (RS) 212 a. To provide high availability and redundancy, western soft switch site 104 includes a redundant SS7 GW, a redundant CS/CDB and a redundant RS. Specifically, western soft switch site 104 includes SS7 GW 210, CS/CDB 206 b and RS 212 b.
Soft switches [0568] 204 a, 204 b and 204 c are connected to SS7 GWs 208, 210, CS/CDBs 206 a, 206 b and RSs 212 a, 212 b via redundant ethernet switches (ESs) 332, 334 having multiple redundant paths. This architecture enables centralization of SS7 interconnection to gain economies of scale from use of a lesser number (than conventionally required) of links to signaling network 114, to be shared by many access servers in gateway sites. ESs 332, 334 also provide connectivity to routers (Rs) 320, 322. Routers 320, 322 respectively provide redundant connectivity between redundant ESs 332, 334 and data network 112. As noted, included in telecommunications network 300 are central soft switch site 106 and eastern soft switch site 302. Central soft switch site 106 and eastern soft switch site 302 respectively include identical configurations to the configuration of western soft switch site 104. Central soft switch site 106 includes SS7 GWs 308, CS/CDBs 312, RSs 314, soft switches 304 a, 304 b, 304 c, ESs 336, 338, and Rs 324, 326. Similarly, eastern soft switch site 302 includes SS7 GWs 310, CS/CDBs 316, RSs 318, soft switches 306 a, 306 b, 306 c, ESs 340, 342, and Rs 328 and 330.
Gateway site [0569] 108 a includes TG 232 a, NAS 228 a, AG 238 a and DACS 242 a. Gateway sites 108 b, 110 a and 110 b have similar configurations to gateway site 108 a. Gateway site 108 b includes TG 232 b, NAS 228 b, AG 238 b and DACS 242 b. Gateway site 110 a includes TG 234 a, NAS 230 a, AG 240 a and DACS 244 a. Finally, gateway site 110 b includes TG 234 b, NAS 230 b, AG 240 b, and DACS 244 b. The details of gateway site 108 a, 108 b, 110 a and 110 b will be further described below with reference to FIG. 10A.
a. Soft Switch [0570]
Referring back to FIG. 2A, soft switch [0571] 204 provides the call processing function for telecommunications network 200. Call processing refers to the handling of voice and data calls. There are a number of important call processing functions handled by soft switch 204. Soft switch 204 processes signaling messages used for call setup and call tear down. These signaling messages can be processed by in-band or out-of-band signaling. For an example of out-of-band signaling, SS7 signaling messages can be transmitted between signaling network 114 and soft switch 204. (Soft switch 204 refers to soft switches 204 a, 204 b and 204 c.)
Another call processing function performed by soft switch [0572] 204 is preliminary digit analysis. Preliminary digit analysis is performed to determine the type of call arriving at soft switch 204. Examples of calls include toll free calls, 1+ calls, 0+ calls, 011+ calls, and other calls recognized by those skilled in the art.
One important feature of soft switch [0573] 204 is communicating with CS/CDB 206 to retrieve important customer information. Specifically, soft switch 204 queries CS/CDB 206 to retrieve a customer trigger plan. The customer trigger plan effectively identifies the service logic to be executed for a given customer.
This trigger plan is similar to a decision tree pertaining to how a call is to be implemented. Subsequently, soft switch [0574] 204 executes the customer trigger plan. This includes the processing of special service calls requiring external call processing, i.e., call processing that is external to the functions of telecommunications network 200.
Another important function soft switch [0575] 204 is communicating with RS 212 to provide network routing information for a customer call. For example, soft switch 204 can query RS 212 to retrieve the route having the least cost from an off-network calling party 102 (homed to gateway site 108) to an off-network called party 120 (homed to gateway site 110) over data network 112. Upon finding the least cost route, soft switch 204 allocates ports on TGs 232, 234. As described in detail below, soft switch 204 can also be used to identify the least cost route termination and allocate gateway ports over AGs 238, 240 between an on-network calling party 122 (homed to gateway site 108) and an on-network called party 124 (homed to gateway site 110).
Soft switch [0576] 204 also communicates with AGs 238, 240, TGs 232, 234, and NASs 228, 230 over data network 112. Although AGs 238, 240, TGs 232, 234 and NASs 228, 230 can communicate with a plurality of soft switches, as illustrated in FIG. 3, these network nodes (referred to collectively as access servers 254 a, 254 b, 256 a, and 256 b) are respectively assigned to a primary soft switch. This primary soft switch, e.g., soft switch 204, assumes a primary responsibility or control of the access servers. In addition, the access servers can be as respectively assigned to secondary switches, which control the access servers in the event that the primary soft switch is unavailable.
Referring back to FIG. 3, western soft switch site [0577] 104, central soft switch site 106 and eastern soft switch site 302 are geographically diverse. For example, western soft switch site 104 can be a soft switch site located in San Diego, Calif. Central soft switch site 106 can be a soft switch site located in Denver, Colo. Eastern soft switch site 302 can be a soft switch site located in Boston, Mass.
It is permissible that additional network nodes are provided at any of soft switch sites [0578] 104, 106 and 302. For example, additional elements, including, e.g., SS7 GW 208, CDB 206 a, and RS 212 a can be collocated at western soft switch site 104. Examples of other supporting elements of western soft switch site 104 are an announcement server (ANS), a network event collection point (NECP), an SCP, and on-network STPs. Referring to the more detailed implementation of FIG. 2A, telecommunications network 200 includes ANSs 246, 248, NECP 224, SCP 214, and STPs 250, 252.
(1) Soft Switch Interfaces [0579]
FIG. 4A is a block diagram illustrating the interfaces between soft switch [0580] 204 and the remaining components of telecommunications network 200. The soft switch interfaces of FIG. 4A are provided for exemplary purposes only, and are not to be considered limiting. Soft switch 204 interfaces with SS7 GWs 208, 210 via soft switch-to-SS7 GW interface 402. One example of interface 402 is an SS7 integrated services digital network (ISDN) user part (ISUP) over a transmission control protocol/internet protocol (TCP/IP). Soft switch 204 interfaces with configuration server 206 over interface 406. In an example embodiment, interface 406 is a TCP/IP connection.
Soft switch [0581] 204 interfaces with RNECP 224 over interface 410. In an example embodiment, interface 410 is a TCP/IP connection.
Soft switch [0582] 204 interfaces with route server 212 over interface 408. In an example embodiment, interface 408 is a TCP/IP connection.
Soft switch [0583] 204 interfaces with SCP 214 over interface 404. In an example embodiment, interface 404 is a TCP/IP connection.
Soft switch [0584] 204 interfaces with announcement servers 246, 248 over interface 416. In an example embodiment, interface 416 can include the IPDC protocol used over a TCP/IP connection.
Soft switch [0585] 204 interfaces with TGs 232, 234 over interface 412. In an example embodiment, interface 412 can include the IPDC protocol used over a TCP/IP connection.
Soft switch [0586] 204 interfaces with AGs 238, 240 over interface 414. In an example embodiment, interface 414 can include the IPDC protocol used over a TCP/IP connection.
In one embodiment, soft switch [0587] 204 is an application software program running on a computer. The structure of this exemplary soft switch is an object oriented programming model discussed below with reference to FIGS. 4B-4E.
Another interface to soft switch [0588] 204 (not shown) is a man-machine interface or maintenance and monitoring interface (MMI). MMI can be used as a direct controller for management and machine actions. It should be noted that this is not intended to be the main control interface, but is rather available to accommodate the need for on-site emergency maintenance activities.
Yet another interface permits communication between soft switches [0589] 204, 304. A soft switch-to-soft switch interface will be described further with reference to FIG. 2B. A soft switch 204-to-soft switch 304 interface permits communication between the soft switches 204, 304 that control the originating call-half and terminating call-half of call flow 258. The soft switch 204-to-soft switch 304 interface allows soft switches 204, 304 to set up, tear down and manage voice and data calls. Soft switch 204 to soft switch 304 interface can allow for a plurality of inbound and outbound signaling types including, for example, SS7, ISDN, and in-band E&M signaling.
In telephony, E&M is a trunking arrangement generally used for two-way (i.e., either side may initiate actions) switch-to-switch or switch-to-network connections. E&M signaling refers to an arrangement that uses separate leads, called respectively the “E” lead and the “M” lead, for signaling and supervisory purposes. The near-end signals the far-end by applying −48 volts DC (“VDC”) to the “M” lead, which results in a ground being applied to the far end's “E” lead. When −48 VDC is applied to the far-end “M” lead, the near-end “E” lead is grounded. “E” lead originally stood for “ear,” i.e., when the near-end “E” lead was grounded, the far end was calling and “wanted your ear.” “M” originally stood for “mouth,” because when the near-end wanted to call (i.e., to speak to) the far end, −48 VDC was applied to that lead. [0590]
When a PBX wishes to connect to another PBX directly, or to a remote PBX or to an extension telephone over a leased voice-grade line (e.g., a channel on a T-1), the PBX can use a special line interface. This special line interface is quite different from that which the PBX uses to interface to directly-attached phones. The basic reason for the difference between a normal extension interface and a long distance interface is that the respective signaling requirements differ. This is true even if the voice signal parameter, such as level and two-wire, four-wire remain the same. When dealing with tie lines or trunks, it is costly, inefficient, and too slow for a PBX to do what an extension telephone would do, i.e., to go off hook, wait for a dial tone, dial, wait for ringing to stop, etc. The E&M tie trunk interface device is a form of standard that exists in the PBX, T-1 multiplexer, voice-digitizer, telephone company world. E&M signaling can take on a plurality of forms. At least five different versions exist. E&M signaling is the most common interface signaling method used to interconnect switching signaling systems with transmission signaling systems. [0591]
The sample configuration depicted in FIG. 2B, can use a soft switch [0592] 204-to-soft switch 304 protocol. In FIG. 2B, the access servers depicted are trunking gateways 232, 234. TGs 232, 234 are connected to the switch circuit network (SCN), i.e., signaling network 114, via SS7 trunks, ISDN trunks, and in-band trunks. The originating soft switch 204 can receive a call over any of these trunks. The signaling information from these SS7, ISDN, and in-band trunks is processed by soft switch 204 to establish the originating call-half. The signaling information processed by soft switch 204, can be used to determine the identity of terminating soft switch 304. The identity of terminating soft switch 304 is required to complete the call.
Originating soft switch [0593] 204 can then communicate the necessary information to complete the call, via an inter-soft switch communication (ISSC) protocol. Terminating soft switch 304 can be required to be able to establish the terminating call-half on any of the supported trunk types. The ISSC protocol can use a message set that is structured similarly to the IPDC protocol message set. The messages can contain a header followed by a number of tag-length-value attributes. The incoming signaling message for the call being placed, can be carried in a general data block of one of the attribute value pairs (AVPs). The other AVPs, can contain additional information necessary to establish a voice-over-IP connection between the originating and terminating ends of the call.
b. SS7 Gateway [0594]
SS7 gateways (GWs) [0595] 208, 210 will now be described further with reference to FIG. 2A and FIG. 5A. In FIG. 2A, SS7 GWs 208, 210 receive signaling messages from signaling network 114 and communicate these messages to soft switch 204. Specifically, for SS7 signaled trunks, SS7 GWs 208, 210 can receive SS7 ISUP messages and transfer them to soft switch 204. SS7 GWs 208, 210 can also receive signaling messages from soft switch 204 and send SS7 ISUP messages out to signaling network 114.
(1) SS7 Gateway Example Embodiment [0596]
In an example embodiment, SS7 GWs [0597] 208, 210 can be deployed in a two (2) computing element (CE) cluster 207, depicted in FIG. 5A. SS7 GWs 208, 210, in two-CE-cluster 207 can fully load-share. SS7 GWs 208, 210 can intercommunicate as represented by connection 530 to balance their loads. Load-sharing results in a completely fault resilient hardware and software system with no single point of failure. Each SS7 GW 208, 210 can have, for example, six two-port cards for a total of twelve links to signaling network 114.
In an example embodiment, SS7 GWs [0598] 208, 210 are application programs running on a computer system. An exemplary application program providing SS7 GW 208, 210 functionality is OMNI SIGNALWARE (OMNI), available from DGM&S, of Mount Laurel, N.J. OMNI is a telecommunications middleware product that runs on a UNIX operating system. An exemplary operating system is the SUN UNIX, available from SUN Microsystems, Inc. of Palo Alto, Calif. The core of OMNI resides logically below the service applications, providing a middleware layer upon which telecommunications applications can be efficiently deployed. Since the operating system is not encapsulated, service applications have direct access to the entire operating environment. Because of OMNI's unique SIGNALWARE architecture, OMNI has the ability to simultaneously support variants of SS7 signaling technology (ITU-T, ANSI, China and Japan).
The SIGNALWARE architecture core is composed of the Message Transfer Part (MTP) Layer 2 and Layer 3, and Service Connection Control Part (SCCP). These core protocols are supplemented with a higher layer of protocols to meet the needs of a target application or service. OMNI supports multiple protocol stacks simultaneously, each potentially with the point code format and protocol support of one of the major SS7 variants. [0599]
OMNI SIGNALWARE Application Programming Interfaces (APIs) are found on the higher layers of the SS7 protocol stack. OMNI APIs include: ISDN User Part (ISUP), Telephony User Part (TUP), Transaction Capabilities Application Part (TCAP), Global System for Mobile Communications Mobile Application Part (GSM MAP), EIA/TIA Interim Standard 41 (IS-41 MAP), Advanced Intelligent Network (AIN), and Intelligent Network Application Part (INAP). [0600]
(2) SS7 Gateway-to-Soft Switch Interface [0601]
FIG. 5A depicts SS7 gateway to soft switch distribution [0602] 500. Soft switches receive signaling messages from signaling gateways. Specifically, for SS7 signaled trunks, SS7 GWs 208, 210 send and receive signals from signaling network 114. SS7 GWs 208, 210 communicate with soft switches 204 a, 204 b, 204 c, via redundant connections from the soft switches 204 a, 204 b, 204 c to distributions 508, 510, of SS7 GWs 208, 210 respectively. SS7 GWs 208, 210 together comprise a CE cluster 207.
Based upon an SS7 network design, a pair of SS7 gateways receive all signaling traffic for the trunking gateway (TG) circuits serviced by the soft switches at a single soft switch site. Specifically, a pair of SS7 GWs [0603] 208, 210 receive all signaling traffic for circuits serviced by soft switch site 104. Signals serviced by soft switch site 104 enter telecommunications network 200 from gateway sites 108, 502, 110.
In an example embodiment, [0604] 96 circuits are serviced by each gateway site 108, 502, 110. Gateway site 108 includes TGs 232 a, 232 b. Gateway site 110 includes TGs 234 a, 234 b. Gateway site 502 includes TGs 504, 506.
A circuit is identified by a circuit identification code (CIC). TG [0605] 232 a includes line card access to a plurality of circuits including CICs 1-48 512 of gateway site 108. TG 232 b provides line card access to CICs 49-96 514 of gateway site 108. TG 504 provides line card access to CICs 1-48 516. TG 506 provides line card access to CICs 49-96 518 of gateway site 502. TG 234 a provides line card access to CICs 1-48 520. TG 234 b provides line card access to CICs 49-96 522 of gateway site 110. Thus, CICs 1-48 512, 516, 520, and CICs 49-96 514, 518, 522 are the trunking gateway circuits serviced by soft switch site 104.
In an example embodiment, soft switches are partitioned such that any single soft switch will only service a subset of circuits serviced at a given soft switch site. For example, soft switch [0606] 204 a can service CICs 1-48 512, 516, while soft switch 204 b services CICs 49-96 514 and CICs 1-48 520, and soft switch 204 c services CICs 49-96 518, 522. In order to assure that all signaling messages for a particular call get to the correct one of soft switches 204 a, 204 b, 204 c, it is necessary to partition SS7 signaling across the available soft switches based upon the circuits that each soft switch services.
It is much more efficient to run SS7 links to soft switches than to each individual access server (compare to the conventional approach requiring an SS7 link to each SSP). Centralization of SS7 signaling traffic interconnection enables benefits from economies of scale, by requiring less SS7 interconnection links. [0607]
An exemplary technique for distributing circuits across soft switches [0608] 204 a, 204 b, 204 c is based upon the originating point code (OPC), destination point code (DPC), and CIC. OPC represents the originating point code for a circuit group, i.e., the point code of a local exchange carrier (LEC) switch, or signal point (SP). For example, the LEC providing CICs 1-48 512, and CICs 49-96 514 can have an OPC 524 of value 777. The LEC providing CICs 1-48 516, and CICs 49-96 518 can have an OPC 526 of value 888. The LEC switch providing CICs 1-48 520, and CICs 49-96 522 has an OPC 528 of value 999. Similarly, DPC represents the destination point code for a circuit group, i.e., the point code of soft switch site 104. Soft switch site 104 has a point code 529 of value 111, and an alternate point code 531 of value 444. Soft switch site 104 can act as one big switch using a flat network design of the present invention. This flat network design simplifies routing of calls.
To support distribution of circuits across soft switches [0609] 204 a, 204 b, 204 c, SS7 GWs 208, 210 can include a lookup table that allows each signaling message to be routed to the correct soft switch 204 a, 204 b, 204 c. The lookup table can route signaling messages to the correct soft switch 204 a, 204 b, 204 c based upon the OPC, DPC, and CIC fields. This lookup table is built on SS7 GWs 208, 210 based upon registration messages coming from soft switches 204 a, 204 b, 204 c.
In an example embodiment, each time a TG boots up, the TG finds a soft switch to service its circuits. For example, when TG [0610] 232 a is powered up, TG 232 a must find a soft switch 204 a, 204 b, 204 c to service its circuits, i.e. CICs 1-48 512. In an exemplary technique, TG 232 a sends registration messages to soft switch 204 a to register circuits CICs 1-48 512. Upon receipt of these registration messages the soft switch 204 a registers these circuits with SS7 GWs 208, 210, at soft switch site 104. The circuit registration messages sent to the SS7 gateways are used to build the type of table shown in Table 6.
OPC, DPC, CIC
Registration Request Value
Message Type SS7 gateway circuit registration
OPC Originating point code for the circuit group.
Equals the LEC point code.
Primary DPC Primary destination point code for the circuit
group. Equals the Soft Switch site point
Alias DPC Alias DPC for the Soft Switch site
Start CIC Starting Circuit Identification Code for the
End CIC Ending Circuit Identification Code for the
Servicing Soft Switch ID Unique Identifier for the Soft Switch that
will service requests for the OPC, DPC, CIC
Servicing Soft Switch IP address for the Soft Switch that will
IP address service requests for the OPC, DPC, CIC
Servicing Soft Switch Port number that the Soft Switch is listening
IP port on for incoming signaling messages.
Primary/Secondary/Tertiary The Soft Switch identifies itself as the
identification primary, secondary or tertiary contact for
signaling messages for the specified OPC,
DPC and CIC.
The format of a registration message is shown in Table 7. Table 7 includes the mapping of circuits to soft switches. [0611]
The messages used by soft switches [0612] 204 a, 204 b, 204 c to register their circuits with SS7 GWs 208, 210 contain information for the OPC, DPC and circuit range, i.e., the CICs that are being registered. Each message also contains information about the soft switch that will be servicing the signaling messages for the circuits being registered.
The soft switch information includes an indication of whether this soft switch is identified as the primary servicing point for calls to these circuits, the secondary servicing point or the tertiary servicing point. The gateway uses this indicator in failure conditions, when it cannot contact the Soft Switch that is currently servicing a set of circuits. [0613]
CIC Soft
OPC DPC Range Switch
777 111 1-48 204a
777 111 49-96 204b
888 111 1-48 204a
888 111 49-96 204c
999 111 1-48 204b
999 111 49-96 204c
FIG. 5A illustrates, and Table 7 represents in tabular form, the associations between circuit trunk groups of TGs [0614] 232 a, 232 b, 516, 518, 520, 522 and soft switches 204 a, 204 b, 204 c. SS7 GWs 208, 210 distribute incoming SS7 signaling messages to the soft switch 204 a, 204 b, 204 c listed as associated with the particular circuit in the circuit to soft switch mapping lookup table, (i.e., Table 7). For example, when the LEC switch, or signaling point, associated with OPC 524 (having point code 777) sends a call to TG 232 b over CIC 55 (of CICs 49-96 514), an IAM message can be created and routed. The IAM includes the following information:
(1) OPC 777 (originating LEC has a point code 777), [0615]
(2) DPC 111 (soft switch site [0616] 104, the “switch” that the LEC believes it is trunking to, has point code 111), and
(3) CIC 55 (the circuit selected by the LEC has circuit identifier code 55). [0617]
The IAM message can then be routed by signaling network [0618] 114 (i.e., the SS7 network) to SS7 GWs 208, 210 at soft switch site 104, having point code 111. SS7 GWs 208, 210 can perform a lookup to Table 7, to identify which of soft switches 204 a, 204 b, 204 c is handling the particular circuit described in the IAM message. In the example above, the IAM message having OPC 524 of value 777, DPC of value 111 and CIC 55 can be routed to soft switch 204 b.
SS7 GWs [0619] 208, 210 will now be discussed further with reference to FIG. 17A. FIG. 17A depicts an exemplary signaling network environment 1700. FIG. 17A includes signaling network 114 Specifically, signaling network 114 can be an SS7 national signaling network. FIG. 17A depicts three soft switch sites interfacing via a plurality of STPs to SS7 network 114.
FIG. 17A includes soft switch sites [0620] 104, 106, 302. Western soft switch site 104 includes three soft switches 204 a, 204 a, 204 b, 204 c redundantly connected to routers 320, 322 and SS7 GWs 208, 210 via ethernet switches 332, 334. SS7 GW 208 and SS7 GW 210 communicate via a TCP/IP connection 1702 and serial link 1704.
Similarly, central soft switch site [0621] 106 includes soft switches 304 a, 304 b, 304 c redundantly connected to routers 324, 326 and SS7 GWs 308 a, 308 b via ethernet switches 336, 338. SS7 GW 308 a and SS7 GW 308 b communicate via TCP/IP connection 1706 and serial link 1708.
Finally, eastern soft switch site [0622] 302 includes soft switches 306 a, 306 b, 306 c redundantly connected to routers 328, 330 and SS7 GWs 310 a, 310 b via ethernet switches 340, 342. SS7 GW 310 a and SS7 GW 310 b communicate via TCP/IP connection 1710 and serial link 1712.
FIG. 17A also includes data network [0623] 112 connected to soft switch sites 104, 106, 302 via routers 320, 322, routers 324, 326 and routers 328, 330, respectively. Data network 112 can carry data including control message information and call traffic information. Data network 112 can also carry in-band type signaling information and ISDN signaling information, via IPDC messages.
Out-of-band signaling, such as, e.g., SS7 signaling, information is communicated to (i.e. exchanged with) soft switch sites [0624] 104, 106, 302 via SS7 GWs 208, 210, SS7 GWs 308 a, 308 b, and SS7 GWs 310 a, 310 b from signaling network 114.
SS7 signaling messages are transferred through signaling network [0625] 114 from STP to STP until arriving at a final destination. Specifically, signaling messages intended for soft switch sites 104, 106, 302, are routed via packet switched SS7 signaling network 114 to STPs 216, 218 which are part of the SS7 national signaling network 114. STP services (i.e., STPs and A-F links) can be provided: by an SS7 signaling services provider, such as, e.g., Transaction Network Services (TNS).
Table 19 defines SS7 signaling links. Some of the SS7 links used are as follows. STPs [0626] 216, 218 are linked together by a C-link. STPs 216, 218 are linked by redundant D-links 1730 to STPs 250 a, 252 a, 1722, 1724, 250 b, 252 b. STPs 216, 218 can also be linked by redundant D-links 1730 to STPs 1718, 1720, 1714, 1716, though this is not shown.
STP pairs [0627] 250 a, 252 a are linked together by one or more C-links 1728. Likewise, STP pairs 1722, 1724, STP pairs 250 b, 252 b, STP pairs 1718, 1720, and STP pairs 1714, 1716 can be linked together by C-links.
STPs [0628] 1714, 1716, 250 a, 252 a, 1722, 1724, 250 b, 252 b, 1718, and 1720 can be linked by one or more A-links 1726 to SS7 GWs 208, 210, 308 a, 308 b, 310 a, and 310 b. Thus, signaling messages from anywhere in signaling network 114 may be routed by STPs 216, 218 through STPs 1714, 1716, 250 a, 252 a, 1722, 1724, 250 b, 252 b, 1718, 1720, to SS7 GWs 208, 210, 308 a, 308 b, 310 a, and 310 b of soft switch sites 104, 106, and 302. SS7 GWs 208, 210, 308 a, 308 b, 310 a, and 310 b thus route messages through packet switched STPs to signaling network 114.
SS7 GWs [0629] 208, 210, 308 a, 308 b, 310 a, and 310 b use a separate physical interface for all simple network management protocol (SNMP) messages and additional functions that may be defined. Exemplary functions that may be defined include provisioning, updating, and passing special alarms, and performance parameters to the SS7 GW from the network operation center (NOC) of network management component 118.
c. Signal Transfer Points (STPs) [0630]
Signal transfer points (STPs) [0631] 216, 218 are the packet switches of signaling network 114. More specifically, STPs are the packet switches of the SS7 network. STPs 250, 252 are the STPs interfacing with SS7 GCs 208, 210 of soft switch site 104. STPs 216, 218 receive and route incoming signaling messages toward the proper destination.
STPs [0632] 250, 252 also perform specialized routing functions. STPs are customarily deployed in pairs. While elements of a pair are not generally collocated, they work redundantly to perform the same logical function.
STPs have several interfaces. STP interfaces are now described, with reference to FIGS. 17A and 17B. The interfaces can be described in terms of the links used. Table 19 shows links used in SS7 architectures. [0633]
The first interface comprises one or more D-links [0634] 1730 from off-network STPs 250, 252 (as shown in FIG. 2A) to on-network STPs 216, 218. D-links connect mated STPs at different hierarchical levels to one another. On-network STPs 216, 218, as well as STPs 1714, 1716, 1722, 1724, 1718 and 1720 are part of the national SS7 signaling network 114. Additional D-links 1730 can connect STPs 216, 218 to STPs 250 a, 252 a, STPs 1722, 1724, STPs 250 b, 252 b, and STPs 1718 and 1720.
The second interface comprises C-links. C-links connect mated STPs together. An example are C-links [0635] 1728 between STP 250 a and 252 a. C-links 1728 enable STPs 250 a, 252 a to be linked in such a manner that they need not be co-located. Similarly, STPs 250 b, 252 b, STPs 1718, 1720, STPs 1722, 1724, STPs 1714, 1716, and STPs 216, 218 can also be respectively linked via C-links.
The third interfaces to STPs comprise A-links and E-links. A-links connect STPs to SSPs and SCPs. E-links are special links that connect SSPs to remote STPs, and are used in the event that A-links to home STPs are congested. The entire soft switch site is viewed as an SSP to a signaling network. A-links or E-links can be used to connect any of STPs [0636] 1714, 1716, 250 a, 252 a, 1722, 1724, 250 b, 252 b, 1718 and 1720 respectively to soft switch sites 104, 106, 302 at SS7 GWs 208, 210, 308 a, 308 b, 310 a and 310 b. In an example embodiment, each of SS7 GWs 208, 210, 308 a, 308 b, 310 a, 310 b can have, for example, twelve (12) A-links 1726 distributed among STPs 250 a, 252 a, 250 b, 252 b and STPs 1714, 1716, 1722, 1724, 1718, 1720. By using the plurality of A-links, the soft switch sites 104, 106, 302 have a fully redundant, fully meshed, fault tolerant signaling architecture.
STPs [0637] 250 a, 252 a, 250 b, 252 b use a separate physical interface for all SNMP messages and additional functions that can be defined. Additional functions that can be defined include provisioning, updating, and passing special alarms and performance parameters to and from STPs 250 a, 252 a, 250 b, 252 b and network operation center (NOC) of network management component 118.
In another embodiment of the invention, as illustrated in FIG. 17B, soft switch sites [0638] 104, 106, 302 have additional soft switches and SS7 GWs. Additional soft switches and SS7 GWs can be used, for example, for handling additional traffic and for testing of alternative vendor soft switches and SS7 GWs.
FIG. 17B includes SS7 gateway to SS7 signaling network alternative embodiment [0639] 1740. FIG. 17B includes signaling network 114 interfacing to western soft switch site 104, central soft switch site 106, and eastern soft switch site 302. Signaling network 114 includes STPs 216, 218 connected via multiple D-Links 1730 to STPs 250 a, 252 a, 250 b, 252 b. In an example embodiment STP 250 a and STP 252 a are connected together by C-Links 1728. In an alternative embodiment, STPs 250 a, 252 a and STPs 250 b, 252 b can be linked by quad B-Links. B-links connect mated STP pairs to other mated STP pairs. STPs 250 a, 252 a, 250 b, 252 b are connected by multiple redundants A-Links 1726 to SS7 GWs in soft switch sites 104, 106, 302.
Western soft switch site [0640] 104 includes SS7 GWs 208, 210, which can communicate via a TCP/IP connection and a serial link. SS7 GWs 208, 210 are connected to soft switches 204 a, 204 b, and 204 c. In addition, western soft switch site 104 includes soft switch 1742 and SS7 GW 1744 connected to STPs 250 a and 252 a. Also western soft switch site 104 includes soft switch 1746 and SS7 GW 1748 connected to STPs 250 a, 252 a.
Central soft switch site [0641] 106 includes SS7 GWs 308 a, 308B which can communicate via a TCP/IP connection or a serial link. SS7 GWs 308 a, 308 b connect soft switches 304 a, 304 b and 304 c to STPs 250 a and 252 a. Central soft switch site 106 also includes soft switch 1750 and SS7 GWs 1752 connected to STPs 250 a, 252 a. Central soft switch site 106 also includes soft switch 1754 connected to SS7 GW 1756, which is connected to STPs 250 a, 252 a.
Eastern soft switch site [0642] 302 includes SS7 GWs 310 a, SS7 GW 310 b, which can communicate over TCP/IP and over a serial link. SS7 GWs 310 a, 310 b connect soft switches 306 a, 306 b and 306 c to STPs 250 b and 252 b. Eastern soft switch site 302 also includes soft switch 1758 connected to SS7 GW 1760, which is connected to STPs 250 b, 252 b. Eastern soft switch site 302 also includes soft switch 1762, which is connected to SS7 GW 1764 which is in turn connected to STPs 250 b, 252 b.
Alternative embodiment [0643] 1740, by including additional soft switches and SS7 gateways, permits additional redundancy and enables testing of alternate devices for connection to signaling network 114 via STPs 250 a, 252 a, 250 b, 252 b, 216 and 218.
(1) STP Example Embodiment [0644]
STPs [0645] 250, 252, in an example embodiment, can be a TEKELEC Network Switching Division's EAGLE STP. An EAGLE STP, available from TEKELEC of Calabasas, Calif., is a high speed packet switch designed to support SS7 signaling. STPs 250, 252 can be equipped with a plurality of links. In an example embodiment, STPs 250, 252 can support up to, for example, 84 links. For example, in a preferred embodiment, 14 links can be used initially, and additional links can be added in the future. In a preferred embodiment, several additional features can be added to STPs 250, 252.
(a) Global Title Translation [0646]
In a preferred embodiment, STPs [0647] 250, 252 can have global title translation capability. Global title translation uses global title information. Global title information is information unrelated to signaling network address, which can be used to determine the appropriate destination of a message. Global title translation can support translations from, for example, one to twenty-one digits. For example, translations can be assigned to translation types from 0 to 225. In a preferred embodiment, STPs 250, 252 can support up to, for example, 1,000 global title translation requests per second, per application service module (ASM).
(b) Gateway Screening Software [0648]
In a preferred embodiment, STPs [0649] 250, 252 include a gateway screening software feature. EAGLE STP can support user definitions of up to 64 screen sets In this embodiment, each screen set can accommodate up to 2,000 condition statements (or rules) with the gateway screening software. Gateway screening can be performed on all in-bound messages from another network. Gateway screening can also be performed on all outgoing network management messages. Since gateway screening can occur on the link interface modules (LIMs) and the application service modules (ASMs), the deployment of the gateway screening feature does not impact link throughput capacity, and can contribute to less than 5 milliseconds increase to cross-STP delays.
(c) Local Number Portability (LNP) [0650]
In a preferred embodiment, local number portability (LNP) can be integrated into the EAGLE architecture of STPs [0651] 250, 252. An advantage of the integration of LNP functionality is that it eliminates the need for costly external LNP databases, and associated transmission equipment. In one embodiment, LNP portability can support, complete scalabilty in configurations ranging from 500,000 translation entries and up to more than several million translation entries for very large metropolitan serving areas (MSAs).
(d) STP to LAN Interface [0652]
In a preferred embodiment, the STP-to-LAN interface of the EAGLE architecture can allow the user to connect external data collection or processing systems directly to STPs [0653] 250, 252 via a TCP/IP protocol. In this embodiment, the STP-to-LAN interface could be used to carry SS7 signaling over IP packets.
(e) ANSI to ITU Gateway [0654]
In a preferred embodiment, STPs [0655] 250, 252 can include a feature referred to as the ANSI-ITU gateway feature. In a preferred embodiment, the ANSI-ITU feature of STPs 250, 252 allows STPs 250, 252 to interconnect three types of signaling networks, i.e., ITU international, ITU national and ANSI, by means of three different message signaling unit (MSU) protocols. In a preferred embodiment of STPs 250, 252, the ANSI-ITU feature can allow a smooth transition from an all-ANSI network to a combined ANSI-ITU network.
d. Services Control Points (SCPs) [0656]
FIG. 6A depicts off-switch called processing abstraction diagram [0657] 600 showing communication mechanisms between soft switch and STPs. FIG. 6A includes at the gateway-facing layer, soft switch processing 604 which can use the IPDC protocol 602, or alternatively, the Network Access Server (NAS) Messaging Interface (NMI) protocol to interface with access servers, or the messaging gateway control protocol (MGCP). IPDC protocol 602 provides a protocol for communications between soft switches and respectively TGs, AGs, NASs and ANSs. Soft switch processing 604 uses IPDC for gateway communication and uses off-switch call processing 606 to access SCPs 608, 614, 618, 620.
SS7 TCAP [0658] 608 is connected to SCP 610 an off-network SCP, via STP 250. IP TCAP 614 is connected to SCP 612. SCP 616 is connected to custom IP 618. SCP 214 is an on-network SCP and is connected via INAP/IP 620.
FIG. 6A represents how some interfaces to soft switch [0659] 204 sit on top of a common interface used by soft switch 204 to handle off-switch call processing. SCPs and other devices, such as route servers, can use this common interface. For example, SCP 610 is an off-network or off-switch SCP, meaning that it is not within soft switch site 104.
Off-switch call processing abstraction layer [0660] 606 is intended to be a flexible interface, similar to TCAP in function, that allows interaction between any type of SCP (or other call processing logic) and soft switch 204. The abstraction layer is so designed that interfaces to a set of call processors supporting a specific function (e.g., 800 service), contain the same types of data, and can all map arguments to data elements supported by off-switch call processing abstraction layer 606. The field values for messages supplied by off-switch call processing abstraction layer 606 are identified in this section (i.e., describing SCPs) and also in the section describing route servers below.
The SCPs can be off-switch call processing servers, which support intelligent services within the telecommunications network SCPs [0661] 610, 612, and 616 can support such services as, for example, account code verification and toll free/800 services, local number portability (LNP), carrier ID identification, and card services.
Other services and capabilities of SCPs [0662] 610, 612, and 616 include basic toll-free services, project account code (PAC) services, local number portability (LNP) services, 800 carrier ID services, calling name (CNAM) services, advanced toll-free/network automatic call distribution (ACD) services, customer premise toll-free routing services, one number (or follow-me) services, and SCP gateway for customer premises equipment (CPE) route selection services. These services are recognized by those skilled in the art.
Additional services and capabilities can include intelligent peripherals. Intelligent peripherals can include calling card, debit card, voicemail, unified messaging, conference calling, and operator services. These peripherals are recognized by those skilled in the art. [0663]
FIG. 6B illustrates intelligent network architecture [0664] 622. FIG. 6B includes gateway site 110, communicating via data network 112, to soft switch 204. The communication can be performed by the H.323 protocol or the IPDC protocol. Soft switch 204 gains signaling information from signaling network 114 via STP 250, through SS7 gateway 208.
Gateway site [0665] 110, in intelligent network architecture 622, is connected to multiple off-network service providers. Off network service providers include local exchange carrier (LEC) 624, inter-exchange (IXC) carrier 626 and operator services service bureau 628. Thus calls coming in from LEC 624 or from IXC 626 into gateway site 110, if identified as an operator call, may be routed to off-network operator services 628.
Soft switch [0666] 204 does not dictate any particular SCP interface, but it is assumed that this interface will support the following types of interactions: (1) route request; (2) route response; (3) call gapping; and (4) connect to resource.
A route request is a message sent from soft switch [0667] 204 to an external SCP 610. The route request is sent to request a translation service from SCP 610, for example, to translate disclosed digits to a destination number.
A route response is a message sent from SCP [0668] 610 to soft switch 204 in response to a route request. The route response includes a sequence of prioritized destinations for the call. SCPs that perform routing can return a list of prioritized destinations. These destinations can be, for example, any combination of destination numbers or circuit groups. If SCP 610 returns a destinations number, soft switch 204 can attempt to route to that destination number using the least cost routing logic included in route server 212. If SCP 610 returns a circuit group, the soft switch 204 can use route server 212 to select an available circuit in that group. Soft switch 204 can try to terminate to the specified destinations in the prioritized order that the destinations are returned from SCP 610.
The interface that can be used by soft switch [0669] 204, in order to interact with SCPs 214, 610, 612, and 616, is called the off-switch call processing (OSCP) interface. This interface is also used for route server 212 and any other call processing engines. OSCP is represented in FIG. 6A as off-switch call processing abstraction layer 606. Tables 8, 9, 10, and 11 identify the fields in the OSCP route request and route response messages, which are necessary for 800 and account code processing service calls.
800 Route Request
SCP Route
Request Parameter 800 SCP - Route Request Value
Message Type 800 Route Request
Call Reference Unique call identifier
Requesting Soft-Switch Soft Switch ID
Bearer Capability Voice, Data or Fax
Destination type DDD (an 8XX number was dialed)
Destination Dialed 8XX number
Originating LATA LATA from IAM or from DAL profile
Calling Number ANI
Originating station type II-digits from IAM or DAL profile
Collected Digits Not Used for 800 processing
Account Code Route Request
OSCP Route
Request Parameter Account Code SCP - Route Response Value
Message Type Account Code Route Request
Bearer Capability Not used for Account Code processing
Destination type Not used for Account Code processing
Destination Not used for Account Code processing
Collected Digits Not Used for Account Code processing
800 Route Response
OSCP Route Request Parameter 800 SCP-Route Response Value
Message Type 800 Route Response
Result Code Success/fail
Number of responses Number of responses sent from the SCP
Destination circuit group - 1 Terminating circuit group for the
first route if the SCP identifies
Destination circuit - 1 Not used for 800 processing
Outpulse digits - 1 Outpulse digits for selected
Destination number - 1 Destination number for the first route
Destination Soft Switch - 1 Not used for 800 processing
Destination circuit group - N Terminating circuit group for the Nth
route, if the SCP identifies circuit
Destination circuit - N Not used for 800 processing
Outpulse digits - N Outpulse digit format for selected
circuit on the Nth route
Destination number - N Destination number for the Nth route
Destination Soft Switch - N Not used for 800 processing
Account Code Route Response
Account Code SCP-Route
OSCP Route Request Parameter Response Value
Number of responses 0 - this is a success/fail response
Destination circuit group - 1 Not used for account code processing
Destination circuit - 1 Not used for account code processing
Outpulse digits - 1 Not used for account code processing
Destination number - 1 Not used for account code processing
Destination Soft Switch - 1 Not used for account code processing
Destination circuit group - N Not used for account code processing
Destination circuit - N Not used for account code processing
Outpulse digits - N Not used for account code processing
Destination number - N Not used for account code processing
Destination Soft Switch - N Not used for account code processing
A route response can also include an indication to initiate a call gapping for a congested call. Call gapping refers to a message sent from an SCP to a soft switch to control the number and frequency of requests sent to that SCP. The call gapping response can indicate a length of time for which gapping should be active, as well as a gap interval, at which the soft switch should space requests going to the SCP. Call gapping can be activated on the SCP for each individual service supported on the SCP. For example, if SCP [0673] 214 supports 800 and project account code queries, it may gap on 800, but not or project account codes. Alternatively, SCP 214 can gap on project codes but not on 800, or can gap on both or neither.
A connect-to resource is a response that is sent from the SCP to the soft switch in response to a route request for requests that require a call termination announcement to be played. [0674]
FIG. 6C illustrates additional off-switch services [0675] 630. For example, calling card interactive voice response (IVR) 632 services can be provided off-switch, similarly to operator services 628. FIG. 6C also depicts on-switch SCP services. Specifically, project account codes (PAC) SCP 214 a and basic toll-free SCP 214 b communicate with soft switch 204 via an INAP/IP protocol 620. Project account codes are discussed further below. Basic toll-free services are also discussed further below.
FIG. 6D depicts additional services [0676] 634. For example, FIG. 6D depicts service node/IP 656, which can be a voice services platform with a voice over IP (VOIP) interface on data network 112. In addition, network IVR 654 is depicted. Network IVR 654 is an IVR that connects to data network 112. Network IVR 654 can communicate with soft switch 204 via the IPDC protocol. Network IVR 654 is also in communication with an advanced toll-free SCP 648, via the SR-3511 protocol.
Advanced toll-free SCP [0677] 648 is in communication with soft switch 204 via INAP/IP protocol 620. Advanced toll-free SCP 648 is also in communication with computer telephony integration (CTI) server 650. CTI server 650 can communicate with an automatic call distributor (ACD) 652.
FIG. 6D also depicts an IP client connected via a customer network into data network [0678] 112. Specifically, IP-Client 660 is connected to data network 112 via customer network 658. Customer network 658 is connected to data network 112 and communicates via an H.323 protocol or via IPDC protocol 602 through data network 112 to soft switch 204. Soft switch 204 is in communication with SS7 gateway 208 via a TCAP/SS7 608 protocol. SS7 gateway 208 is in turn in communication with STP 208 via a TCAP/SS7 608 protocol. STP 208 in turn can communicate with SCPs in the SS7 network via the TCAP/SS7 608 protocol. Specifically, STP 208 can communicate with local number portability (LNP) SCP 636 and also 800 carrier SCP 610. Soft switch 204 can still communicate with PAC SCP 214A and basic toll-free SCP 214B via an INAP/IP 620 protocol. Soft switch 204 can also communicate with an SCP gateway 638 via an INAP/IP 620 protocol. SCP gateway 638 can be used to communicate with customer premises toll-free 640 facilities. Customer premises toll-free 640 facilities can communicate with computer telephony integration (CTI) server 642. CTI server 642 can be in communication with an automatic call distributer (ACD) 644.
The H.323 Recommendation will now be briefly overviewed with reference to FIGS. [0679] 71A-E The H.323 standard provides a foundation for, for example, audio, video, and data communications across IP-based networks, including the Internet. By complying with the H.323 Recommendation, multimedia products and applications from multiple vendors can interoperate, allowing users to communicate without concern for compatibility. H.323 will be the foundation of future LAN-based products for consumer, business, entertainment, and professional applications.
H.323 is an umbrella recommendation from the International Telecommunications Union (ITU) that sets standards for multimedia communications over Local Area Networks (LANs) that do not provide a guaranteed Quality of Service (QoS). These networks dominate today's corporate desktops and include packet-switched TCP/IP and IPX over Ethernet, Fast Ethernet and Token Ring network technologies. Therefore, the H.323 standards are important building blocks for a broad new range of collaborative, LAN-based applications for multimedia communications. [0680]
The H.323 specification was approved in 1996 by the ITU's Study Group 16. Version 2 was approved in January 1998. The standard is broad in scope and includes both stand-alone devices and embedded personal computer technology as well as point-to-point and multipoint conferences. H.323 also addresses call control, multimedia management, and bandwidth management as well as interfaces between LANs and other networks. [0681]
H.323 is part of a larger series of communications standards that enable videoconferencing across a range of networks. Known as H.32X this series includes H.320 and H.324, which address ISDN and PSTN communications, respectively. [0682]
FIG. 58A depicts a block diagram of the H.323 architecture for a network-based communications system [0683] 5800. H.323 defines four major components for network-based communications system 5800, including: terminals 5802, 5804 and 5810, gateways 5806, gatekeepers 5808, and multipoint control units 5812.
Terminals [0684] 5802, 5804, 5810 are the client endpoints on the LAN that provide real-time, two-way communications. All terminals must support voice communications; video and data are optional. H.323 specifies the modes of operation required for different audio, video, and/or data terminals to work together. It is the dominant standard of the next generation of Internet phones, audio conferencing terminals, and video conferencing technologies.
All H.323 terminals must also support H.245, which is used to negotiate channel usage and capabilities. FIG. 58B depicts an exemplary H.323 terminal [0685] 5802. Three other components are required: Q.931 for call signaling and call setup, a component called Registration/Admission/Status (RAS), which is a protocol used to communicate with a gatekeeper 5808; and support for RTP/RTCP for sequencing audio and video packets.
Optional components in an H.323 terminal are video codecs, T.120 data conferencing protocols, and MCU capabilities (described further below). [0686]
Gateway [0687] 5806 is an optional element in an H.323 conference. FIG. 59 depicts an example H.323 gateway. Gateways 5806 provide many services, the most common being a translation function between H.323 conferencing endpoints and other terminal types. This function includes translation between transmission formats (i.e. H.225.0 to H.221) and between communications procedures (i.e. H.245 to H.242). In addition, gateway 5806 also translates between audio and video codecs and performs call setup and clearing on both the LAN side and the switched-circuit network side. FIG. 59 shows an H.323/PSTN Gateway 5806.
In general, the purpose of gateway [0688] 5806 is to reflect the characteristics of a LAN endpoint to an SCN endpoint and vice versa. The primary applications of gateways 5806 are likely to be:
Establishing links with analog PSTN terminals. [0689]