Abstract:
PSTN Internet Notification (PIN) services that can be provided as part of interconnecting IP and Public Switched Telephone Network (PSTN) systems with the intent of converging existing and creating new hybrid PSTN and IP services. PSTN Events Notification, based on well-defined PIN protocols, will promote interoperability of both the networks and systems built by different vendors.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This applicatioin claims priority of Provisional Application Ser. No. 60/120,604 which was filed Feb. 18, 1999. 
    
    
     TECHNICAL FIELD 
     This invention relates to public switched telephone network (PSTN) to internet services and more particularly to PSTN-Internet notification (PIN) services. 
     BACKGROUND 
     Telephone calls and telephone call services that are well known within the PSTN are starting to be available on communication systems that use both the PSTN and the Internet network as their telephone call transport media. 
     “Current telephone call services on the PSTN system and those available on the PSTN-Internet system are described in the articles: ITU-T Q.12 Recommendation Series, Geneva, 1995; I. Faynberg, L. R. Gabuzda, M. P. Kaplan, and N. J. Shah, “The Intelligent Network Standards and their Application to Services” McGraw-Hill, 1996; S. Petrack, “IP Access to PSTN Services: Basic Service Requirements, Definitions, and Architecture”, Internet Draft; Handley, Schulzrinne, Schooler, and Rosenberg, “SIP: Session Initiation Protocol”, Internet Draft; “Proposal for Internet Call Waiting Service using SIP; L. Slutsman, “Advanced Internet Caller ID Delivery Service” Internet Draft; and J. Rosenberg, H. Schulzrinne, “SIP For Presence”, Internet Draft.” 
     Those articles referred to as Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work in progress.” Copies of the above mentioned articles as of Feb. 18, 1999 will be available to establish the state of the art. The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/l id-abstracts.txt 
     The problem of the telephone services referred to in the above articles is that they are just most rudimentary telephone services, while users and PSTN service providers and Internet service providers would like to provide the same telephone services on PSTN-Internet systems that are available on PSTN systems. 
     It is an object of this invention to provide advanced telephone services to PSTN-Internet system users. 
     It is another object of this invention to provide a method for enabling advanced PSTN-Internet services. 
     SUMMARY 
     In accordance with one aspect of the invention, the aforementioned object are achieved by providing a method for use with a communication system in which a set of PIN clients have subscribed to an incoming call notification event service having the subscription information saved in a database accessible to a service notification function unit (SNF) and a PIN server, comprising the steps of: 
     a. Calling party initiating a call that gets to a terminating switch (TS); 
     b. TS notifying a SNF entity of the system of this event and alerting Called Party in the normal manner of Called Party&#39;s telephone will ring on the Called Party&#39;s side; 
     c. SNF communicating to the PIN Gateway, passing the PIN Gateway the Calling Party&#39;s number, the Called Party&#39;s number, the time of day the call was received and other information related to the call, said communicating between the SNF and PIN Gateway occur using existing PSTN domain protocols; 
     d. PIN Gateway passing said information to the PIN Server using a PIN protocol. 
     e. PIN Server consulting the database to get the appropriate PIN Client&#39;s IP address; and 
     f. PIN Server notifying the appropriate PIN Client of the Incoming Call; wherein communications between the PIN Server and PIN Clients use either PIN or some other relevant IP domain protocol. 
     In accordance with another aspect of the invention, the aforementioned objects are achieved by providing a method for use with a communication system in which a set of PIN clients have subscribed to a Voice Mail Arrival Event service having the subscription information saved in a database accessible to the SNF and the PIN server, comprising the steps of: 
     a. Calling party initiating a call that gets to the Terminating Switch (TS); 
     b. The TS notifying SNF entity of the system of this event and alerting Called Party in the normal manner of Called Party&#39;s telephone will ring on the Called Party&#39;s side and the call will be forwarded to a voice mail system; 
     c. SNF communicating to the PIN Gateway, passing the PIN Gateway the Calling Party&#39;s number, the Called Party&#39;s number, the time of day the call was received and other information related to the call, said communicating between the SNF and PIN Gateway occur using existing PSTN domain protocols; 
     d. PIN Gateway passing said information to the PIN Server using a PIN protocol. 
     e. PIN Server consulting the database to get the appropriate PIN Client&#39;s IP address; and 
     f. PIN Server notifying the appropriate PIN Client of the Incoming Call; wherein communications between the PIN Server and PIN Clients use either PIN or some other relevant IP domain protocol. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a simplified block diagram of a PSTN-Internet system useful for practicing the invention. 
     FIG. 2 is a flow diagram of an incoming call notification event service on a PSTN-Internet system. 
     FIG. 3 is a flow diagram of a voice mail arrival event service on a PSTN-Internet system. 
    
    
     TABLE OF ABBREVIATIONS 
     CPL Call Processing language 
     DN Destination Number 
     ICW Internet Call Waiting 
     IN Intelligent Network 
     NPL Notification Processing Language 
     PINT PSTN Internet Interworking Group 
     PSTN Public Switched Telephone Network 
     SCP Service Control Point 
     SIP Session Initiation Protocol 
     SN Service Node 
     VoIP Voice over IP (Internet Protocol) 
     DETAILED DESCRIPTION 
     Referring now to FIG. 1, a representative network is shown. PSTN-Internet notification (PIN) services will be described. In order to provide interoperability between PSTN and IP networks, it is very important to ensure notification of the IP network portion of the PSTN-Internet system of the events happening in the PSTN portion. PSTN events of which the Internet portion needs to be notified can be grouped into two categories: 
     Category I: Basic events 
     1. Phone off-hook. 
     2. Phone on-hook. 
     3. Voice-mail Arrival. 
     4. Incoming Call Notification (Attempt to Terminate Call). and 
     Category II: Advanced events 
     1. Attempt to dial number (specific event can be Attempt to Dial ISP Number. 
     2. Dropping Dialed Connection (i.e. dropping ISP call). 
     3. ISP Connection Made. 
     4. Attempt to Forward Call (forwarded end point could easily be VoIP terminal). 
     5. Attempt to Subscribe/Unsubscribe for a PSTN Service (i.e. Set Up Call Forwarding). 
     6. Attempt to Enter Conference. 
     7. Attempt to Exit Conference. 
     8. Identification of the Speaker (talking party) to the other participants of the Voice (or multimedia) Conference. 
     The Basic events have been well known in the PSTN network for a long time. The Advanced events have some that have been known for a long time, such as Attempt to Forward Call. These known Advanced events will take on a broader meaning when they can and do refer to PSTN-IP calls in addition to PSTN-PSTN calls. Other Advanced events did not exist until PSTN-IP calls made them possible, such as the ISP Made event. PSTN events are important because they are include data upon which services are built and operate. 
     Some examples of services that are based on PIN of PSTN events, or use PIN of PSTN events as one of the building blocks thereof are: 
     1. Internet Call Waiting. ICW is the capability to provide incoming call notification and completion options when the Subscriber is on a dial-up IP connection. 
     2. Internet Call Management. PSTN call notification and control options (flexible call screening, forwarding, etc.), delivered to an IP client. 
     3. Internet Conference Management. PSTN Teleconference notification and management from an IP Client 
     4. Internet Conference Mediation. Pre-Teleconference (before an actual connection is made) management service from an IP client. 
     5. Advanced Caller ID Delivery: Ordered incoming call notification to multiple Subscriber&#39;s dial-up IP connections. 
     6. Queue Management. Notification of the status and events of the call queue, much needed for the IP-based Call Center Control. 
     7. Call Progress Delivery as part of PINT services. Classic PINT services need notification of the Call Progress. 
     8. Internet Call Routing (ICR). Flexible routing and control over a dial up PSTN call from an IP host. 
     Thus, in support of call feature services that PSTN customers are familiar with, in an IP portion of a PSTN-IP network, a method for transmitting PSTN events to an IP portion of a PSTN-IP network and use of those events in the IP portion, such as that provided by the present invention, was needed. 
     Architecture of the Invention 
     With the proliferation and wide acceptance of the Internet, and more so with the convergence of the Internet and PSTN, e.g. system  100 , there is an increasing desire for events occurring on the PSTN domain to be propagated to the Internet domain. A PIN protocol transmitting notifications of PSTN events to the Internet domain fills this need. Entities on the Internet domain can receive the events generated by the PSTN domain and act appropriately. The major entities of the PIN services and protocol are the PIN gateway  104 , the PIN servers  106 ,  108  and various PIN clients  110 ,  112 , as depicted in FIG. 1 which illustrates a functional scalable architecture that will support PIN Services. 
     FIG. 1 Legend: 
     SNF—Service Notification Function unit  102   
     .-.—PIN Protocol 
     ---—PIN Protocol or Standard Client Server Protocol 
     ...—Standard PSTN/SS7/IN Protocol 
     A Service Notification Function (SNF) unit  102  is located in PSTN domain. SNF  102  may physically reside in IN elements (e.g. be a part of SCP, SMS, or SSP) that are specialized servers. Alternatively SNF  102  may be connected to telephone switches and other PSTN elements (not shown in FIG.  1 ). PSTN informs SNF  102  and PIN Gateway  104  of PSTN events utilizing traditional protocols (SS7/IN) PIN Server provides Subscription for Notification Services and aggregates Notification Services for PIN Clients  110 ,  112 . PIN protocol is a specialized protocol used for communication between the PIN gateway and PIN servers, as well as between PIN servers and PIN clients. PIN protocol communicates specific PIN messages. It must be a real time protocol in order to support the call feature services. One embodiment of the present invention uses standard SNMP (simple network management protocol) as the PIN protocol. Another embodiment uses SIP (session initiation protocol) as the PIN protocol. Other protocols are contemplated for use as a PIN protocol, but as of this time they are not completed. The PIN messages that the PIN protocol carries include fields for at least the following information fields: 
     Calling Number 
     Called Number 
     Caller Name 
     Event Type (like on-hook, off-hook, ISP number recognition, etc.) 
     Call treatment (priority call, QoS, etc.) 
     Charge rate 
     Charge type (credit card, operator assisted, collect call, etc.) 
     Timestamp 
     Call disposition (terminated by VoiceMail system, answering machine, modem, pager, etc.) 
     The present invention uses PIN Protocol to communicate event information from PIN Gateway  104  to PIN Servers  106 ,  108  and from PIN Servers  106 ,  108  to PIN Clients  110 ,  112 . The invention also uses the Notification Processing Language (NPL), which has a current status but is also evolving according to the actions of the IPTEL Working Group industry group. NPL also is used for defining connections of the Basic Notification Services to the PSTN Call states. NPL facilitates the building of new Notification Services and provides means to describe Notification Filters for Notification screening. An example of a Notification Filter is: Notification for an Attempt to Enter Conference from a predefined number in the hours 9 through 17 only on weekends and holidays. 
     Referring now to FIGS. 2 and 3, the systems  200  and  300  respectively have SNFs  204 ,  304  that are respectively connected to terminating switches  202 ,  302 ; PIN Gateways  206 ,  306 ; and databases  220 ,  320 . The databases  220  and  320  are designed with essential database schema: 
     Subscribed PIN client&#39;s profile table; 
     Client identification; 
     IP address(es); 
     authentication information (including public/private keys, if needed); and 
     set of interested PIN event(s) 
     Please note, this is not an exhaustive list of database fields and schema, but does represent the minimum needed to implement PIN services of the present invention. 
     Examples of PIN Services 
     Service 1: Incoming Call Notification Event. Scenario: A set of PIN clients want to know, in real time, all incoming calls for a particular PSTN number is shown in FIG.  2 . In FIG. 2 the system  200  has a set of PIN clients that are subscribed to Incoming Call Notification Event. This subscription information is saved in a database  220  that is accessible to the SNF and the PIN Server. 
     Step 1: Calling party initiates a call that gets to the Terminating Switch (TS)  202 . 
     Step 2: The TS  202  notifies the SNF entity  204  of this PSTN event. The Called Party is alerted in the normal manner (i.e. the phone will ring on the Called Party&#39;s side). 
     Step 3: SNF  204  communicates to the PIN Gateway  206 , passing it the Calling Party&#39;s number, the Called Party&#39;s number, the time of day the call was received and any other pertinent information. Communications between the SNF  204  and PIN Gateway  206  occur using existing PSTN domain protocols (SS7, IN). 
     Step 4: PIN Gateway  206  passes this information to the PIN Server  208  using a PIN protocol (e.g. SIP or SNMP). 
     Step 5: PIN Server  208  consults a database  220  to get an appropriate PIN Client&#39;s IP address. 
     Step 6: PIN Server  208  notifies the appropriate PIN Client  210  or  212  of the Incoming Call. Upon receiving notification of a PSTN event, the PIN client may handle the notification of the PSTN event internally. The PIN client may handle the PSTN event by emitting an audible signal, emitting a visible signal, or by logging the notification to a disk file.” 
     After the incoming call is established, communications between the PIN Server  208  and PIN Client  210  or  212  may use PIN or some other relevant IP domain protocol. 
     Service 2: Voice Mail Arrival Event. Scenario: A set of PIN clients  310  and  312  want to know, in real time, all the calls that went to voice mail box for a particular PSTN number (as shown in FIG.  3 ). In FIG. 3, a system  300  has a set of PIN clients  310 ,  312  that are subscribed to the Voice Mail Arrival Event. This subscription information is saved in a database  320  that is accessible to the SNF  304  and the PIN Server  208 . 
     Step 1: Calling party initiates a call that gets to the Terminating Switch (TS)  302 . 
     Step 2: The TS  302  notifies the SNF entity  304  of this PSTN event. The Called Party is alerted in the normal manner (i.e. the phone will ring on the Called Party&#39;s side, and the call will be forwarded to a voice mail system). Note that, alternatively, the voice mail system can also notify the SNF  304  of this event. In the diagram above, however, the TS  302  is shown notifying the SNF  304  of this event. 
     Step 3: SNF  304  communicates to the PIN Gateway  306 , passing to PIN Gateway  306  the Calling Party&#39;s number, the Called Party&#39;s number, the time of day the call was received and any other pertinent information. Communications between the SNF  304  and PIN Gateway  306  occur using existing PSTN domain protocols (SS7, IN). 
     Step 4: PIN Gateway  306  passes this information to the PIN Server  308  using a PIN protocol (e.g. SIP or SNMP). 
     Step 5: PIN Server  308  consults the database  320  to get an appropriate PIN Client&#39;s IP address. 
     “Step 6: PIN Server  308  notifies the appropriate PIN Client  310  or  312  of the Incoming Call. Upon receiving notification of a PSTN event, the PIN client may initiate a process to handle the notification of the PSTN event. The PIN client may initiate an email client process or initiate a short messaging client process for notifying a short-messaging endpoint unit that may comprise a pager, cellular telephone, or a personal communications system. The PIN client may initiate a process to handle the notification of the PSTN event by initiating a facsimile delivery to a PSTN endpoint process.” 
     After the incoming call is established, communications between the PIN Server  308  and PIN Client  310  or  312  may use PIN or some other relevant IP domain protocol. 
     Other PIN services similar to these are possible by this invention. For example: 
     Security Considerations 
     PIN communications between the PIN Client, PIN Server, PIN Gateway and the SNF may travel over the Internet. Thus it is essential to provide encryption for the communications. In addition to encryption, it is also necessary to provide authentication of both the end points; i.e. SNF and PIN Client. PIN security has to authenticate both end points and if the authentication succeeded, encrypt the communications. 
     PIN Security Requirements are, similar to PINT Security Requirements outlined in the articles mentioned above. They include: 
     Peer entity authentication to allow a communicating entity to prove its identity to another in the network. 
     Non-repudiation to account for all operations in case of doubt or dispute. This could be achieved by logging all the information pertinent to the transaction. In addition, the PSTN network will maintain its own account of the transaction for generating bills. 
     Confidentiality to avoid disclosure of information without the permission of its owner. Although this is an essential requirement, it is not particular to the proposed project. 
     PIN Client profile verification to verify if the end user is authorized to use a service. 
     In the course of the development, additional requirements are likely to arise and many more specific security work items are likely to be proposed and implemented. 
     Some of the PIN-specific security considerations: 
     Cracking is a threat to any Service Provider (PSTN, Intranet, Internet). It is real danger—phone companies are common targets 
     Notification spoofing is one of the threats 
     Existing mechanisms applied to the Internet can be implemented 
     Stealing a Notification is a new type of security threat 
     As can be appreciated, security is an important part of PSTN-Internet communications and thus an important part of PIN services. 
     Although this invention has been described with respect to a preferred embodiment, those skilled in the art may devise numerous other arrangements without departing from the scope of the invention as defined in the following claims.