Patent Publication Number: US-8121028-B1

Title: Quality of service provisioning for packet service sessions in communication networks

Description:
RELATED APPLICATIONS 
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     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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     MICROFICHE APPENDIX 
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     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to packet services in communication networks, and in particular, to the provisioning of quality of service levels for service sessions. 
     2. Description of the Prior Art 
     Recently, cable companies have begun to offer voice services in addition to the standard data and entertainment services of the past. The most common voice service offered is voice over packet (VoP), of which Voice over Internet Protocol (VoIP) is a well known example. Cable companies that offer multiple types of services are often times referred to as multi-system operators, or MSOs. 
     End users, such as residential and business customers, are accustomed to high levels of quality of service (QoS) from circuit switched voice providers, such as the local exchange carriers (LECs) that form portions of the public switched telephone network (PSTN). In order to compete with circuit switched voice providers, MSOs must be able to provide QoS at comparable levels. 
       FIG. 1  illustrates a communication network  100  in the prior art for providing QoS in a cable MSO network. Communication network  100  includes cable network  110 , access system  105 , destination system  120 , end system  101 , proxy system  112 , and policy decision function (PDF) system  111 . In communication network  110 , cable network  110  provide transport for communications between access system  105  and destination system  120 . Access system  105  provides end system  101  with access to cable network  110 . End system  101  is typically connected to access system  105  by a hybrid fiber/coaxial connection (HFC). Cable network  110  is often times a high-speed Ethernet network, such as Gig-Ethernet. Proxy system  112  is typically a session initiation protocol (SIP) proxy system. Likewise, end system  101  could include a SIP end device. Proxy system  112  operates in accordance with well known protocols, such as SIP). 
     In operation, end system  101  registers with proxy system  112 , including transmitting the network address of end system  101 , such as its IP address, to proxy system  112 . Proxy system  112  stores the current network address of end system  101  for later call processing. 
       FIG. 2  illustrates the operation of communication network  100  for provisioning QoS for a VoP session between end system  101  and destination system  120  in an example of the prior art. To begin, end system  101  transmits a SIP invite message to proxy system  112 . The invite message indicates an identifier for end system  101  and a destination identifier for destination system  120 . Proxy system  112  typically processes the invite message to perform call setup processes to setup a VoP call between end system  101  and destination system  120 . As part of the call setup process, proxy system  112  transmits a QoS request to PDF system  111 . The request indicates the network address for end system  101 . In response, PDF system  111  looks up the requested QoS information and transmits the resulting QoS information to access system  105 . Access system  105  configures the links between end system  101  and access system  105  in accordance with the QoS information. The appropriate QoS level is then applied to the VoP session between end system  101  and destination system  120 . 
     One prior problem illustrated by  FIG. 2  is that the current network address of end system  101  is required by PDF system  111  and access system  105  in the QoS provisioning process. In many cases, MSOs partner with third-party carriers to provide VoP services to the MSO customers. However, common boundary devices, such as session border controllers, block actual network addresses from passing across peered network borders. As a result, MSOs face increasing challenges in their attempts to provide high levels of QoS to customers who have become accustomed to the high QoS of the PSTN. In addition, carriers face increased challenges to their ability to provide QoS control over sessions originating from or terminating to a peered MSO network due to the presence of session border controllers. 
     SUMMARY OF THE INVENTION 
     An embodiment of the invention helps solve the above problems and other problems by providing systems and methods that allow a carrier network to retain call control over sessions originating from or terminating to a peered MSO network, even though visibility across the networks is reduced due to the presence of session border controllers. 
     In an embodiment of the invention, a communication system comprises an end system coupled to an access system and configured to transmit an invite message for a session wherein the invite message indicates a destination and an alias for the end system, a proxy system configured to receive the invite message and transfer a quality request wherein the policy request indicates the alias, a policy system configured to receive the quality request, determine a quality level for the session and transmit a quality message to the access system indicating the alias and the quality level, and the access system configured to receive the quality message, transmit a query to a database system indicating the alias, receive a network address for the end system in response to the query, identify traffic for the session using the network address, and apply the quality level to the traffic. 
     In an embodiment of the invention, the access system comprises a cable modem termination system (CMTS). 
     In an embodiment of the invention, the end system comprises a device coupled to a modem. 
     In an embodiment of the invention, the network address is a dynamic Internet Protocol (IP) address for the modem. 
     In an embodiment of the invention, the alias comprises a hard coded domain name service (DNS) name for the modem. 
     In an embodiment of the invention, the database system comprises a domain name service (DNS) server. 
     In an embodiment of the invention, the session comprises a voice over Internet Protocol (VoIP) session. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The same reference number represents the same element on all drawings. 
         FIG. 1  illustrates a communication network in an example of the prior art. 
         FIG. 2  illustrates a flow diagram in an example of the prior art. 
         FIG. 3  illustrates a communication network in an embodiment of the invention. 
         FIG. 4  illustrates a flow diagram in an embodiment of the invention. 
         FIG. 5  illustrates a flow diagram in an embodiment of the invention. 
         FIG. 6  illustrates a communication network in an embodiment of the invention. 
         FIG. 7  illustrates a flow diagram in an embodiment of the invention. 
         FIG. 8  illustrates a flow diagram in an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIGS. 3-8  and the following description depict specific embodiments of the invention to teach those skilled in the art how to make and use the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these embodiments that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple embodiments of the invention. As a result, the invention is not limited to the specific embodiments described below, but only by the claims and their equivalents. 
     First Embodiment Configuration and Operation—FIGS.  3 - 5   
       FIG. 3  illustrates communication network  300  in an embodiment of the invention. In this embodiment, the actual network address of an end system may be used by certain network elements, such as an access system, for configuring a session for QoS. Further in this embodiment, an alias identifier may be used by other network elements, such as a proxy system or a PDF system, for determining and informing the access system of the appropriate QoS. A database system is provided for correlating the network address of an end system with the alias identifier for the end system. 
     In particular, communication network  300  includes service network  310 , access system  305 , destination system  320 , end system  301 , proxy system  312 , PDF system  311 , and database system  315 . End system  301  is operatively coupled to access system  305 . Access system  305  is operatively coupled to service network  310 . Database system  315 , proxy system  312 , PDF system  311 , and destination system  320  are also operatively coupled to service network  310 . Service network  310  could be any network or collection of networks configured to provide transport and control for the exchange of communications, such as session bearer and control traffic, as well as other types of communications. 
     Access system  305  is any system capable of providing service access for end system  301  to service network  310 . Access system  305  is also any system capable of providing QoS treatment to service sessions between end system  301  and destination system  320 . Examples of service sessions include VoP sessions, video sessions, and gaming sessions, as well as other types of sessions. In one example, access system  305  could be a cable modem termination system (CMTS), as well as other types of access systems. 
     End system  301  is any system capable of participating as an end system on a session with destination system  320 . End system  301  could be a system of collection of systems, such as a wireless or wireline phone, personal digital assistant, multi-media devices, pager, or modem, as well as other types of systems. Destination system  320  could be any system or collection of systems capable of participating with end system  301  on a session. 
     Proxy system  312  could be any system capable of providing session control for sessions between end system  301  and destination system  320 . For instance, proxy system  312  could be capable of communicating with PDF system  311  to determine QoS levels for sessions between end system  301  and destination system  320 . Proxy system  312  could be a system or collection of systems. For example, proxy system  312  could be a sub system in a soft-switch. Proxy system  312  could be a stand-alone system separate from a soft-switch. Proxy system  312  could also be considered a soft-switch itself. Other variations are possible. In one example, proxy system  312  could be a SIP proxy server, as well as other types of proxy systems. 
     PDF system  311  could be any system capable of communicating with proxy system  312  and access system  305  to coordinate and provision QoS for sessions between end system  301  and destination system  320 . PDF system  311  could be an individual system or collection of systems. 
     Database system  315  could be any system capable of storing network addresses in association with alias identifiers. In addition, database system  315  could be any system capable of receiving registration messages indicating network addresses and their associated alias identifiers. Furthermore, database system  315  could be any system capable of receiving and processing queries from access system  305  and transmitting responses back to access system  305 . 
       FIG. 4  is a flow diagram illustrating the operation of communication network  300  in an embodiment of the invention. In this embodiment, QoS is provisioned for a session between end system  301  and destination system  320 . To begin, end system  301  registers its alias identifier (ID) and actual network address with database system  315 . Next, end system  301  transmits a registration message to proxy system  312  notifying proxy system  312  of the presence of end system  301  and the alias ID of end system  301 . Proxy system  312  can then use the information for well known call processing. At this stage, database system  315  holds the current network address for end system  301  and the alias ID for end system  301 . The alias ID does not identify the current network address. 
     After completing the registration process, a user desires to place a VoP call to destination system  320 . In response to a user input, such as dialing a phone number, end system  301  transmits an invite message to proxy system  312 . The invite message identifies destination system  320 , such as by the phone number, as the alias ID of end system  301 . Proxy system  312  processes the invited in accordance with well known call processing, including transmitting a QoS request to PDF system  311 . However, in a departure from the prior art, the QoS request indicates the alias ID for end system  301 , rather than the actual network address. 
     Upon receiving the QoS request from proxy system  312 , PDF system  311  processes the request to determine the appropriate QoS for the requested session between end system  301  and destination system  320 . PDF system  311  determines the QoS in accordance with well known principles, such as by performing a table lookup. The lookup could be performed based on a user ID associated with the user using end system  301 , the alias ID of end system  301 , or the ID of access system  305 . Other well known ways of determining the QoS are possible. 
     After determining the QoS, PDF system  311  transmits a message to access system  305  indicating the QoS and the alias ID for end system  301 . Access system  305  receives the message and transmits a query to database system  315  indicating the alias ID. Database system  315  processes the query to determine the network address associated with the alias ID. Upon determining the network address, database system  315  transmits a response to access system  305  indicating the network address associated with the alias ID. Access system  305  is advantageously able to identify session traffic associated with the network address and apply the correct QoS treatment to the session traffic. 
       FIG. 5  is a flow diagram further illustrating the operation of communication network  300  in an embodiment of the invention. In  FIG. 5 , a two-way session flow is illustrated, although a session could be one-way. In this embodiment, end system  301  transmits session communications to access system  305 . Access system  305 , knowing the network address of end system  301 , applies the appropriate QoS to the session communications. For instance, access system  305  could provide priority to the session communications in preference over other types of communications, such as non-voice communications. Other types of prioritization are possible. Access system  305  forwards the session communications to communication network  310 . Communication network  310  in turn transports the communications to destination system  320 . 
     In the opposite direction, destination system  320  transmits session communications to communication network  310 . Communication network  310  transports the communications to access system  305 . Access system  305  applies the appropriate QoS to the session communications, and forwards the communications to end system  301 . End system  301  provides the communications in a usable form, such as an audio or video output, to a user. 
     Although not pictured, the following describes the session termination process with respect to  FIGS. 3-5 . Once the session is concluded, end system  301  transmits a termination message to proxy system  312 . Proxy system  312  passes a control message to PDF system  311  indicating the alias ID for end system  301  and instructing PDF system  311  to release access system  305  from the QoS requirements for the session. PDF system  311  responsively transmits a release message to access system  305  to release the session QoS parameters. The release message identifies end system  301  by the alias ID. Access system  305  queries database system  315  with the alias ID to determine the actual network address linked to the alias ID. Database system  315  processes the query and returns the current network address of end system  301  to access system  305 . Access system  305  receives the response and clears the QoS requirements associated with the network address. Access system  305  responds to PDF system  311  with a success message. PDF system  311  passes the success message to proxy system  312  to complete the session termination process. 
     Second Embodiment Configuration and Operation—FIGS.  6 - 8   
       FIG. 6  illustrates communication network  600  in an embodiment of the invention. In this embodiment, communication network  600  allows a carrier network to retain call control over sessions originating from or terminating to a peered MSO network, even though visibility across the networks is reduced due to the presence of session border controllers. In this embodiment, a modem obtains a dynamic Internet Protocol (IP) address from a dynamic host configuration protocol (DHCP) server. The modem then registers its alias address and its dynamic IP address with a global domain name server. A SIP device connected to the modem registers with a SIP proxy server using the alias address of the modem. Upon initiating a session between the SIP device and a phone on the PSTN, the proxy server communicates with a PDF server using the alias address to configure the session QoS. The PDF server in turn communicates with a cable modem termination system (CMTS) on a cable MSO network using the alias address to provision the QoS. The CMTS queries the global DNS system to resolve the alias address of the modem to its dynamic IP address. The CMTS is then able to identify session traffic from the modem and apply the required QoS. 
     Communication network  600  includes cable network  660 , carrier network  670 , PSTN  680 , and hybrid fiber coax (HFC) network  650 . Devices  641 ,  642 , and  643  are operatively coupled to modems  651 ,  652 , and  653  respectively. Modems  651 ,  652 , and  653  are operatively coupled by HFC  650  to CMTS  655 . Cable network  660  operatively couples CMTS to session border controller (SBC)  663 . SBC  663  is operatively coupled to SBC  673 . Proxy system  672 , PDF system  671 , and gateway  675  are operatively coupled together by carrier network  670  and to SBC  673 . Gateway  675  operatively couples carrier network  670  to PSTN  680 . Phone  681  is coupled to PSTN  680 . DNS system  690  is in communication with cable network  660  and carrier network through SBCs  663  and  673  respectively. 
     Cable network  660  could be any network typical of MSO networks. For example, cable network  600  could be a high-speed Gig-Ethernet network. HFC network  650  could be comprised of fiber links, coaxial cable links, or both. Devices  641 ,  642 , and  643  could be any kind of device capable of communicating with modems  652 ,  652 , and  653 . For example, devices  641 ,  642 , and  643  could be computers, phones, or other types of devices. CMTS  655  could be capable of delivering data services over HFC  650  to modems  651 ,  652 , and  653 . More particularly, CMTS  655  could be configured to provide QoS for services in accordance with the packet cable multimedia (PCMM) specification. CMTS  655  could communicate with modems  651 ,  652 , and  653  over DOCSIS 1.1 or 2.0 links, as is well understood in the art. 
     SBC  663  could be any session border controller capable of controlling session traffic across the border between cable network  660  and carrier network  670 . Similarly, SBC  673  could be any session border controller capable of controlling session traffic across the border between cable network  660  and carrier network  670 . Carrier network  670  could be any network capable of providing VoP services to end users of cable network  660 . Carrier network  670  could be, for example, a packet core network capable of terminating sessions to or from cable network  660  and to or from PSTN  680 . Gateway  675  could be any gateway system capable of interfacing between carrier network  670  and PSTN  680 . Gateway  675  could be capable of interworking both bearer traffic and signaling traffic. 
     Proxy system  672  could be any system capable of providing call control for sessions originating from and terminating to end users in cable network  660 . For example, proxy system  672  could be a SIP proxy configured to provide call control for SIP VoP sessions originating from or terminating to devices  641 ,  642 , and  643 . In another example, proxy system  672  could be configured to communicate with PDF system  671  to determine session QoS levels for individual sessions. SIP proxies are well known in the art. Proxy system  672  could also be referred to as a soft switch. Proxy system  672  could also be integrated into a soft switch. Alternatively, proxy system  672  could be a stand alone element separate from a soft switch. 
     PDF system  671  could be any system capable of communicating with proxy system  672  and CMTS  655  to provision session QoS. PDF system  671  could be configured to operate in accordance with the common open policy service (COPS) protocol. COPS is a standard for exchanging policy information in order to support dynamic QoS in IP networks. In this case, PDF system  671  could be considered a policy decision point (PDP), whereas CMTS  655  could be considered a policy enforcement point (PEP). 
       FIG. 7  is a flow diagram illustrating the operation of communication network  600  in an embodiment of the invention. To begin, modem  651  is powered on and automatically transmits an address request to DHCP server  664 . DHCP server  664  returns a dynamic IP address to modem  651 . Next, modem  651  registers the dynamic IP address and its hard-coded DNS name with DNS system  690 . The hard-coded DNS name of modem  561  could identify a phone number for the modem, the cable MSO that operates cable network  660 , and a region of the cable network in which modem  651  resides. For instance, the hard-coded address could be 7855551212.cablemso.region22. Other aliases could be used. 
     Next, a user using VoIP enabled device  641  desires to place a call to phone  681  on PSTN  680 . In response, device  641  transmits a SIP invite message to proxy system  672 . The invite message could identify the hard-coded modem address or ID and a destination ID for phone  681 . The destination ID could be, for example, a PSTN phone number. In response to the invite message, proxy system  672  performs call setup for the session, including transmitting a QoS request to PDF system  671 . In one example, proxy system  672  uses a SOAP/XML interface to pass along the session description protocol (SDP) information from the original invite message to PDF system  671 . The original SDP information includes the hard-coded modem address. 
     The PDF request indicates the hard-coded modem address. PDF system receives the QoS request and determines a QoS level for the session involving modem  651 , as identified by the hard-coded modem address. PDF system  671  transmits a quality message to CMTS  655  indicating the hard-coded modem address and the QoS level. PDF system  671  could communicate with CMTS  655  in accordance with COPS based PCMM. CCMTS  655  receives the quality message and queries DNS system  690  with the hard-coded modem address. DNS system  690  processes the query, including performing a look-up to a table based on the hard-coded modem address. DNS system  690  returns a response indicating the dynamic IP address stored in association with the hard-coded modem address. CMTS  655  then uses the dynamic IP address to identify and configure a network path for the session traffic according to the specified QoS level. Once the QoS levels have been set, CMTS  655  transmits a success message to PDF system  671 . PDF system  671  passes the success message to proxy system  672  and the session is allowed to proceed. 
       FIG. 8  is a flow diagram illustrating the flow of session traffic during a VoP session in communication network  600 . In one direction, device  641  transfers session traffic, such as voice data, to modem  651 . Modem  651  transfers the traffic to CMTS  655 . CMTS  655  applies the appropriate QoS, such as by prioritizing the VoP traffic over other types of non-VoP traffic. CMTS  655  then transmits the traffic to SBC  663 . SBC  663  recognizes the session traffic and passes it to SBC  673 . SBC  673  has been configured by proxy system  672  to route the traffic over carrier network  670  to gateway  675 . Gateway  675  interworks the traffic from an asynchronous packet format to a time division multiplexed (TDM) format suitable for transport over PSTN  680  to phone  681 . 
     In the opposite direction, session traffic, such as voice communications, is transferred from phone  681  to PSTN  680 . PSTN  680  routes the traffic to gateway  675 . Gateway  675  interworks the traffic from a TDM format to an asynchronous packet format suitable for transport over carrier network  670  to SBC  673 . SBC  673  has been configured by proxy system  672  to route the traffic to SBC  663 . Likewise, SBC  663  has been configured to route the traffic to CMTS  655 . CMTS  655  applies the appropriate QoS levels to the session traffic and forwards the traffic over HFC  650  to modem  651 . Modem  651  then provides the session traffic to device  641 . Device  641  plays out the traffic in an audio or video form suitable for a user. 
     The following describes the call process that occurs at the conclusion of the session. To conclude the session, end device  641  transmits a bye message to proxy system  672 . Using the SOAP/XML interface, proxy system  672  transmits the SDP information from the original invite message, including the hard-coded modem address, to PDF system  671 . Proxy system  672  also sends a request to PDF system  671  to release the QoS handling for the session. PDF system  671  receives the release request and sends a release request to CMTS  655  to release the QoS requirements. The release request indicates the hard-coded modem address for modem  651 . CMTS  655  again queries DNS system  690  to resolve the hard-coded modem address to its current dynamic IP address. Upon receiving the dynamic IP address from DNS system  690 , CMTS  655  clears the appropriate QoS gates on the data streams associated with the dynamic IP address and responds with a success message to PDF system  671 . PDF system  671  communicates the success message to proxy system  672 , and the call is successfully terminated. 
     Advantageously, communication network  600  allows carrier network  670  to retain call control over sessions originating from and terminating to cable network  660  even though visibility across the networks is reduced by the presence of session border controllers.