Abstract:
Methods, systems, and computer program products for providing presence-qualified E.164 number mapping (ENUM) service in a communications network. According to one method, a query message including an E.164 number can be received. Next, at least one uniform resource identifier (URI) associated with the E.164 number can be located. A presence server can be queried for presence status information for the URI. Further, the query message can be responded to with the URI and a corresponding presence status.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application entitled “Systems and Methods for Providing Presence Qualified ENUM Service in a Communications Network”, and filed Apr. 15, 2005, the disclosure of which is incorporated by reference herein in its entirety. 
     
    
     TECHNICAL FIELD  
       [0002]     The subject matter described herein relates to providing E.164 number mapping (ENUM) service in a communications network. More particularly, the subject matter described herein relates to methods, systems, and computer program products for providing presence-qualified ENUM service in a communications network.  
       BACKGROUND ART  
       [0003]     The Internet Engineering Task Force (IETF) initiated the development of the E.164 Number Mapping (ENUM) system for facilitating the interconnection of communications networks that rely on telephone numbers with the communications networks that utilize the Domain Name System (DNS). In particular, the ENUM system can map a particular number referred to as an E.164 number to one or more Uniform Resource Identifiers (URIs) in the DNS. URIs are strings of characters that identify resources such as documents, images, files, databases, e-mail addresses, websites or other resources or services in a common structured format. A URI can include a SIP URI, an instant messaging (IM) identifier, an e-mail address identifier, an Internet chat session identifier, and an IP address.  
         [0004]      FIG. 1  is an exemplary communications network, generally designated  100 , utilizing the ENUM system. Network  100  includes a gateway  102  for connecting the Public Switched Telephone Network (PSTN) system  104  to an IP Multimedia Subsystem (IMS)  106 . Gateway  102  is operable to enable communication between a conventional telephone unit or other suitable network device connected to PSTN  104  and a mobile telephone unit or other suitable network device connected to IMS  106 . The mobile telephone unit can communicate to IMS  106  via session initiation protocol (SIP) proxy server  108 . The conventional telephone unit and mobile telephone unit can communicate voice data, text data, or other suitable data. ENUM system can be utilized, for example, when a user of the standard telephone unit attempts to reach a subscriber associated with the mobile telephone unit.  
         [0005]     Communication between the conventional telephone unit and the mobile telephone unit can be initiated when a user of the conventional telephone unit dials a called party number (referred to herein as an E.164 number) for reaching a subscriber associated with the mobile telephone unit. A message containing the dialed E.164 number (or called party number) is routed to PSTN  104 . PSTN  104  can then generate an ISUP IAM message  110  containing the E.164 number to gateway  102  which can determine whether the E.164 number is associated with the subscriber. Gateway  102  can determine whether the E.164 is associated with the subscriber by performing a lookup in a subscriber database. In response to determining that the telephone number is associated with the subscriber, the E.164 number is converted into ENUM message format for transmission in an ENUM query  112 . The E.164 number is converted to ENUM message format by reversing the digit order of the dialed E.164 number and appending the highest level domain e164.arpa to the end. For example, if the original E.164 number is 123-456-7890, ENUM query  112  is converted 0.9.8.7.6.5.4.3.2.1.e164.arpa (also referred to herein as an E.164 number). Next, the ENUM query is then communicated to an ENUM server  114 . ENUM server  114  uses the ENUM query to retrieve one or more naming authority pointer (NAPTR) records associated with the E.164 number. Each of the NAPTR records may identify at least one URI corresponding to the subscriber with the E.164 number. The URI may identify the mobile telephone unit. The URI is then communicated to gateway  102  in an ENUM response  116  for establishing communication between the conventional telephone unit and the mobile telephone unit.  
         [0006]     In addition, more than one URI can be contained in the NAPTR records for identifying one or more other network devices, services and/or addresses. For example, another URI returned to gateway  102  can identify a different way of reaching the subscriber associated with the dialed E.164 number, such as via e-mail or paging.  
         [0007]     Rather than simply returning the URI or set of URIs obtained from ENUM server  114  to gateway  102 , it may be desirable to obtain additional information, such as presence information for contacting the called party. Presence is a service that provides for the monitoring of the availability and disposition of services and/or addresses identified by URIs. Presence information is highly dynamic and generally characterize whether a user is online or offline, busy or idle, away from communications devices or nearby, and the like. Presence information is typically stored in a presence database. In order to obtain presence information regarding a subscriber, referred to as a presentity, a subscribing entity must send a subscribe message to a presence server if presence information for the subscribed-to presentity is available in the presence database, the presence server will respond with presence information for the presentity. If presence information regarding the presentity changes, the presence server will send presence update messages to subscribing entities.  
         [0008]     As described above, the mechanisms for obtaining ENUM and presence information are distinct. However, it may be desirable to combine presence information with ENUM information to obtain enhanced contact information for a subscriber with multiple ENUM identities. Currently, such a combined mechanism does not exist. That is, a subscriber wishing to obtain presence information for multiple ENUM identities would be required to manually subscribe to or query a presence server for each ENUM identity.  
         [0009]     Accordingly, in light of these difficulties associated with conventional ENUM systems, there exists a need for improved methods, systems, and computer program products for providing a combination of ENUM and presence services in a communications network.  
       SUMMARY  
       [0010]     According to one aspect, the subject matter described herein comprises methods, systems, and computer program products for providing presence-qualified E.164 number mapping (ENUM) service in a communications network. One method includes receiving a query message including an E.164 number. Next, at least one uniform resource identifier (URI) associated with the E.164 number can be located. A presence server can be queried for presence status information for each URI. As used herein, the term “presence status information” refers to information indicating whether the subscriber is available or unavailable at the corresponding URI. Further, the query message can be responded to with each URI that has an available presence status.  
         [0011]     Another method according to the subject matter described herein includes communicating a presence subscription request associated with a URI to a presence server. The method can also include receiving presence status information updates associated with the URI from the presence server. Further, the method can include storing the presence status information. The method can also include using the stored status information to respond with URIs associated with the E.164 number that have an available presence status in response to receiving an ENUM query including an E.164 number.  
         [0012]     The subject matter described herein providing presence qualified ENUM mapping may be implemented using a computer program product comprising computer executable instructions embodied in a computer readable medium. Exemplary computer readable media suitable for implementing the subject matter described herein includes disk memory devices, programmable logic devices, application specific integrated circuits, and downloadable electrical signals. In addition, a computer readable medium that implements the subject matter described herein may be distributed across multiple physical devices and/or computing platforms. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     Preferred embodiments of the subject matter described herein will now be explained with reference to the accompanying drawings of which:  
         [0014]      FIG. 1  is an exemplary communications network utilizing the ENUM system;  
         [0015]      FIG. 2  is an exemplary system for providing presence-qualified ENUM service in a communications network according to an embodiment of the subject matter described herein;  
         [0016]      FIG. 3  is a flow chart illustrating exemplary steps for providing presence-qualified ENUM service in a communications network according to an embodiment of the subject matter described herein;  
         [0017]      FIG. 4  is an exemplary system including a presence server operable to provide presence subscription service to an ENUM server according to an embodiment of the subject matter described herein;  
         [0018]      FIGS. 5A and 5B  are a flow chart illustrating exemplary steps by which a presence server can provide presence subscription service to an ENUM server according to an embodiment of the subject matter described herein;  
         [0019]      FIG. 6  is a message flow timing diagram of an ENUM server establishing a presence subscription service with a presence server according to one embodiment of the subject matter described herein; and  
         [0020]      FIG. 7  is a message flow timing diagram of a presence server providing presence update information to an ENUM server according to one embodiment of the subject matter described herein. 
     
    
     DETAILED DESCRIPTION  
       [0021]      FIG. 2  illustrates an exemplary system for providing presence-qualified ENUM service in a communications network, generally designated  200 , according to an embodiment of the subject matter described herein. Referring to  FIG. 2 , the system can include an ENUM server  202  and a presence server  204  in operable communication with one another and with network  200 . Network  200  can include a gateway  206  for providing communication between a PSTN  208  and an IMS  210 . Further, gateway  206  can receive signaling messages for establishing communication between an end device in communication with PSTN  208  and IMS  210 . For example, gateway  206  can receive message from PSTN  208  for establishing communication between a telephone unit  212  connected to PSTN  208  and a subscriber identified in the message by an E.164 number. Alternatively, gateway  206  can receive messages from any suitable source for establishing communication with a subscriber identified by an E.164 number.  
         [0022]     Gateway  206  may determine whether an ENUM query is required based on whether the called party number corresponds to a subscriber of IMS network  210 . If gateway  206  determines that an ENUM query is required, gateway  206  can transmit an ENUM query to ENUM server  202 . ENUM server  202  can include an input/output (I/O) module  214  for receiving the ENUM query from gateway  206 . The ENUM query may contain E.164 number. The E.164 number may be a called party telephone number. ENUM server  102  may also include an ENUM application  216  for performing a lookup in an ENUM database  218  for retrieving one or more URIs associated with the received E.164 number. For example, ENUM database  218  can maintain naming authority pointer (NAPTR) records associated with the URIs. The URIs are associated with the subscriber identified by the E.164 number.  
         [0023]     Next, ENUM server  202  can utilize another I/O module  220  for communicating a query message containing the retrieved one or more URIs to presence server  204 . The query message can be a request for presence status information for one or more of the URIs. Presence server  204  can maintain a database  222  containing presence status information for the URIs. In response to receiving the query message from ENUM server  202 , presence server  204  can perform a lookup in database  222  to retrieve presence status information of each of the URIs. The retrieved presence status information for each URI can indicate the availability or unavailability associated with the URI. Presence server  204  can transmit to ENUM server  202  a response message containing the presence status information for one or more of the URIs. Based on the presence status information, ENUM server  202  can generate a response message containing availability and/or unavailability information for one or more URIs associated with the E.164 called party telephone number of the ENUM query. The response message can be communicated to gateway  206 .  
         [0024]     In one embodiment, ENUM server  202  responds to the ENUM query with only those URIs that were designated as available by presence server  204 . By transmitting a message identifying only the available URIs, the complexity of processes implemented by gateway  206  can be reduced to thereby improve the processing efficiency of gateway  206 . Alternatively, ENUM server  202  can respond to the ENUM query with the availability information for all URIs, even those that are currently unavailable.  
         [0025]     One of the URIs identified as available in the response to gateway  206  may identify a mobile telephone  224  connected to IMS  210  via a SIP proxy  226 . Gateway  206  may utilize the URI for establishing communication between telephone unit  212  and mobile telephone  224 . Alternatively, gateway  206  can communicate one or more URIs identified in the response message to telephone unit  212  for informing a user of the availability of the subscriber associated with the E.164 number.  
         [0026]      FIG. 3  is a flow chart illustrating exemplary steps for providing presence-qualified ENUM service in communications network  200  according to an embodiment of the subject matter described herein. Referring to  FIG. 3 , in step  300 , a network device, such as gateway  206 , can receive an E.164 number or called party number. Pursuant to IETF ENUM specifications, the network device can convert the E.164 number to an ENUM message format (step  302 ). For example, referring to  FIG. 2 , if the E.164 number is 123-456-7890, an ENUM query message  228  may read 0.9.8.7.6.5.4.3.2.1.E164.arpa. In this conversion example, the digit order of the telephone number is reversed, and the highest level domain E164.arpa is appended at the end. Next, at step  304 , gateway  206  can communicate ENUM query message  228  to ENUM server  202  as described above. ENUM query  228  may be implemented utilizing a signaling protocol such as session initiation protocol (SIP).  
         [0027]     At step  306  of  FIG. 3 , ENUM application  216  can utilize ENUM query message  228  for performing a lookup in ENUM database  218  to retrieve one or more URIs associated with the received E.164 called party number. Exemplary URIs associated with E.164 number 0.9.8.7.6.5.4.3.2.1.E164.arpa include sip:john@companydesk.com, mailto:john@serviceprovider.com, sip:johnhome@company123.com, and mailto:jhome@serviceprovider.com.  
         [0028]     Next, at step  308 , ENUM server  202  can communicate a presence query message containing the one or more URIs to presence server  204 . For example, referring to  FIG. 2 , a presence query message  230  can include the URIs associated with E.164 number 0.9.8.7.6.5.4.3.2.1.E164.arpa. Database  222  of presence server  204  can maintain data for indicating presence status information of the URIs in the query message. In the example shown in  FIG. 2 , the only URIs available are sip:john@companydesk.com and mailto:john@serviceprovider.com. In response to receiving a query message from ENUM server  202 , presence server  204  can perform a lookup in database  222  for retrieving presence status information of each of the URIs contained within the query message (step  310 ). The presence status information can be availability and/or unavailability information for one or more of the URIs associated with presence query message  230 .  
         [0029]     Next, at step  312  of  FIG. 3 , presence server  204  can communicate to ENUM server  202  a presence response message  232  containing the retrieved presence status information for one or more of the URIs. Based on received message  232 , ENUM application  216  can generate an ENUM response message containing availability and/or unavailability information for one or more URIs associated with the E.164 number in the original ENUM message. For example, ENUM response message  234  indicates that the only URIs available are sip:john@companydesk.com and mailto:john@serviceprovider.com. At step  314 , ENUM server  202  can communicate ENUM response message  234  to gateway  206 .  
         [0030]     According to one embodiment, the presence server or the ENUM server may be provided with information in addition to the E.164 number. For example, the presence server may be provided with calling party information such that the presence server may apply calling party “blacklist” or “whitelist” screening algorithms. These algorithms may be utilized for determining which URIs to return in response to an ENUM query. For example, callers identified in a calling party “blacklist” may be prevented from transmitting messages to the subscriber identified by the E.164 number. In contrast, callers identified in a calling party “whitelist” may be permitted to transmit messages to the subscriber identified by the E.164 number.  
         [0031]     With respect to  FIGS. 2 and 3 , the ENUM and presence servers are described as separate devices. According to one embodiment, the functionality of the ENUM and presence servers may be combined into a single device. For example, the functionality of ENUM server  214 , ENUM application  216 , and database  222  may be combined into a single device operable to receive an ENUM query identifying an E.164 number of a subscriber, operable to respond to the ENUM query with one or more available URIs for the subscriber.  
         [0032]     According to another embodiment, a presence server may provide a presence subscription service to a network device such as ENUM server  202 . In this embodiment, the presence server may report presence status changes of URIs.  FIG. 4  illustrates an exemplary system including a presence server  400  operable to provide presence subscription service to an ENUM server  402  according to an embodiment of the subject matter described herein. Referring to  FIG. 4 , ENUM server  402  can transmit a presence subscription request message  406  to presence server  404 . Presence subscription request message  406  can contain a request for presence status information for different URIs, such as all or a subset of URIs maintained in database  218 . In the illustrated example, message  406  contains a request for status changes of the following URIs: sip:john@companydesk.com, mailto:john@serviceprovider.com, sip:johnhome@company123.com, and mailto:jhome@serviceprovider.com.  
         [0033]     Presence server  404  can transmit a message indicating the availability status of each subscribed URI upon receiving a presence subscription request. Further, presence server  404  can generate and transmit a presence update message  408  when a change is made to the status of a URI for which a subscription has been established. For example, message  408  can contain an update on the availability information for each URI requested in message  406 . The availability information can be contained in a database  410  accessible by presence server  404 . ENUM server  402  can maintain a database  412  containing availability information for each subscribed URI. The updated availability information contained in message  408  can be used for updating database  412 .  
         [0034]     A gateway  414  can generate and transmit an ENUM query message  416  containing an E.164 number for requesting availability information associated with the E.164 number. In this example, the E.164 number is 0.9.8.7.6.5.4.3.2.1.E164.arpa. In response to receiving message  416 , ENUM server  402  can search database  412  based on the E.164 number contained in message  416 . Next, ENUM server  402  can retrieve the records having an available presence status and generate and transmit an ENUM response message  418  containing the URIs indicated as available. Alternatively, as described above, ENUM server  402  may respond with all of the URIs corresponding to the E.164 number and indicate the subscriber is available or whether unavailable at each URI. In this example of utilizing presence subscription service, it is not necessary to transmit a query message to presence server  404  for availability information because database  412  of ENUM server  402  is maintained with updated availability information.  
         [0035]      FIGS. 5A and 5B  illustrate a flow chart of exemplary steps by which presence server  404  can provide presence subscription service to ENUM server  402  according to an embodiment of the subject matter described herein. Referring to  FIG. 5A , in step  500 , an ENUM application of ENUM server  402  can generate and communicate a presence request message to presence server  204  to identify one or more of the URIs for which presence status information updates are requested. At step  502 , presence server  404  can perform a lookup in database  410  for retrieving presence status information of each of the URIs identified within the presence subscription request. The presence status information can be availability and/or unavailability information for one or more of the URIs associated with presence query message. The retrieved presence status information can be utilized for communicating a response to ENUM server  202  to indicate the availability and/or unavailability of the URIs (step  504 ).  
         [0036]     The ENUM application of ENUM server  402  can generate an ENUM response message containing availability and/or unavailability information for one or more URIs associated with the E.164 number in the original ENUM message. At step  506  of  FIG. 5 , ENUM server  402  can communicate the ENUM response message to gateway  414 . Further, ENUM server  402  can store the presence status information communicated from presence server  404 . The presence status information may be stored in ENUM database  412  and indexed according to its associated URI. The stored presence status information may then be available for subsequent requests for presence status information. In this way, ENUM server  402  will not have to query presence server  404  for a URI for which presence status information is stored.  
         [0037]     Further, in response to receiving a presence subscription request, presence server  404  can provide presence status changes for the one or more URIs for which a subscription has been requested. At step  508 , presence server  404  can monitor the availability and/or unavailability of the identified URIs. Next, at step  510 , presence server  404  can determine whether an update has been made to one or more of the identified URI. If it is determined that an update has been made, presence server  404  can communicate to ENUM server  402  presence status update information associated with the updated URI (step  512  shown in  FIG. 5B ). Next, at step  514  of  FIG. 5B , ENUM server  402  can update the presence status information for the URI. Returning to step  510 , if there are no updates, presence server  204  can continue to monitor for updates at step  510 .  
         [0038]     In step  516  of  FIG. 5B , gateway  414  can receive an E.164 number. Gateway  414  can then convert the E.164 number to an ENUM message format (step  518 ). Next, at step  520 , gateway  206  can communicate an ENUM query containing the converted E.164 number to ENUM server  402 .  
         [0039]     At step  522  of  FIG. 5B , the ENUM application can utilize the ENUM query for performing a lookup in ENUM database  412  to retrieve one or more URIs associated with the received E.164 number. Next, ENUM server  402  can generate and transmit an ENUM response message indicating the available URIs associated with the E.164 number.  
         [0040]     While ENUM server  402  is subscribed to availability update information from presence server  404  for a URI, presence server  404  can continually monitor for updates to the availability information for the URI under subscription. When there is an update to the availability information, presence server  404  can communicate the update to ENUM server  402 . By the communication of updates of presence status information, it may only be necessary for ENUM server  402  and presence server  404  to communicate when presence status information for a URI requires updating and when ENUM server  402  does not have presence status information stored for a particular URI for which information is requested.  
         [0041]     In one exemplary implementation, SIP or SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) protocol may be used for implementing presence subscription service between an ENUM server and a presence server. For example, ENUM server  402  and presence server  404  are operable to implement SIMPLE protocol for establishing a presence subscription service.  FIG. 6  is a message flow diagram of an ENUM server  600  establishing a presence subscription service with a presence server  602  according to one embodiment of the subject matter described herein. Referring to  FIG. 6 , in line  1  of the message flow diagram, ENUM server  402  transmits to presence server  404  a subscription request message containing a URI for which presence subscription service is requested. Presence server  404  authenticates the subscription request message and, if the request is authenticated, in line  2  transmits a “200 OK” message acknowledging the request. In line  3 , presence server  404  transmits a notification message containing the current availability information for the URIs contained in the subscription request. ENUM server  600  can store the availability information and associate it with the URI. In line  4 , ENUM server  600  transmits a “200 OK” message, acknowledging receipt of notification message  608 .  
         [0042]      FIG. 7  is a message flow diagram illustrating presence server  404  providing presence update information to ENUM server  402  according to one embodiment of the subject matter described herein. Referring to  FIG. 7 , in line  1  of the message flow diagram, presence server  402  generates and transmits a message containing update presence status information when a change is made to the status of the URI for which a subscription has been established. The presence status information can include availability and/or unavailability information for the URI. In response to receiving message, in line  2 , ENUM server  402  transmits a “200 OK” message. ENUM server  402  can updated its stored availability information with the updated status information of message of line  1 .  
         [0043]     It will be understood that various details of the subject matter described herein may be changed without departing from the scope of the subject matter described herein. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation, as the subject matter described herein is defined by the claims as set forth hereinafter.