Backend Polling Based on Nonzero SIP Subscribe Expiration

Abstract

Methods and computing systems for SIP backend polling based on nonzero SIP subscribe expiration are described. A SIP server receives from a SIP client a Session Initiation Protocol (SIP) subscribe message indicating a nonzero expiration time. Based at least on receipt of the subscribe message indicating a nonzero expiration time, the SIP server initiates a backend polling session to a backend server. The SIP server receives, via the backend polling session, state information and provides the state information to the SIP client.

What is claimed is: 
     
         1 . A computing system comprising:
 one or more processors;   memory; and   one or more program modules stored on the memory and executable by the one or more processors to:   receive from a computing device a Session Initiation Protocol (SIP) subscribe message indicating a nonzero expiration;   determine to utilize a backend polling mechanism;   determine at least one backend server, of a plurality of backend servers, the at least one backend server being determined based at least in part on requested state information included in the SIP subscribe message;   transmit to the at least one backend server a SIP polling subscribe message;   receive the state information from the at least one backend server; and   provide the state information to the computing device.   
     
     
         2 . The computing system of  claim 1 , wherein the one or more program modules are further executable by the one or more processors to determine to utilize the backend polling mechanism based on the nonzero expiration being less than or equal to a predetermined expiration threshold. 
     
     
         3 . The computing system of  claim 1 , wherein the one or more program modules are further executable by the one or more processors to determine to utilize the backend polling mechanism based on a further condition comprising a characteristic of the computing device. 
     
     
         4 . The computing system of  claim 1 , wherein the one or more program modules are further executable by the one or more processors to determine to utilize the backend polling mechanism based on a further condition comprising a past behavior of the computing device. 
     
     
         5 . The computing system of  claim 4 , wherein the past behavior of the computing device includes termination of an SIP subscription after receiving initial state information. 
     
     
         6 . The computing system of  claim 4 , wherein the past behavior of the computing device includes ending a session prior to an expiration time of a previous subscription. 
     
     
         7 . The computing system of  claim 1 , wherein the computing system comprises a video call system. 
     
     
         8 . The computing system of  claim 1 , wherein the one or more program modules are further executable by the one or more processors to determine to utilize a persistent subscription session with the computing device in response to receiving the SIP subscribe message indicating a nonzero expiration. 
     
     
         9 . The computing system of  claim 1 , wherein the SIP subscribe message indicates a request for at least one of capability or presence information for one or more contacts, and wherein the state information includes the at least one of capability or presence information for one or more contacts. 
     
     
         10 . The computing system of  claim 1 , wherein the computing device includes a Rich Communication Services (RCS) client. 
     
     
         11 . A method of operating a server, the method comprising:
 receiving from a SIP client a Session Initiation Protocol (SIP) subscribe message indicating a nonzero expiration time;   initiating a backend polling session to a backend server based at least on receipt of the SIP subscribe message indicating a nonzero expiration time and on a first characteristic of the SIP client matching at least one of a second characteristic of a predetermined list of characteristics, the first characteristic of the SIP client including at least one of a client device operating system type, a client device operating system version, or a client device manufacturer, wherein a subscribe message transmitted to the backend server to initiate the backend polling session indicates a zero expiration time;   receiving, via the backend polling session, state information; and   providing the state information to the SIP client.   
     
     
         12 . The method of  claim 11 , further comprising:
 determining that the nonzero expiration time is less than or equal to a predetermined threshold time; and   initiating the backend polling session to the backend server with a zero expiration time based on the nonzero expiration time being less than or equal to the predetermined threshold time.   
     
     
         13 . The method of  claim 11 , wherein the SIP subscribe message indicates a request for at least one of presence information associated with a contact or capabilities information associated with a contact. 
     
     
         14 . Non-transitory computer-readable media storing instructions executable by one or more processors to perform acts comprising:
 receiving a request from a client device to establish a Session Initiation Protocol (SIP) subscription, the request indicating a session timeout greater than zero;   establishing the SIP subscription with the client device;   initiating, to a backend server, a backend polling subscription having a timeout equal to zero in response to the request indicating the session timeout greater than zero and being less than or equal to a predetermined expiration threshold;   determining a percent chance that that the client device will receive state information based at least in part on client device characteristics, the percent chance being used to determine the expiration threshold; and   providing, to the client device via the SIP subscription, state information obtained from the backend server via the backend polling subscription.   
     
     
         15 . The non-transitory computer-readable media of  claim 14 , wherein the acts further comprise determining to initiate the backend polling subscription having the timeout equal to zero based on the request indicating a session timeout greater than zero. 
     
     
         16 . The non-transitory computer-readable media of  claim 14 , wherein the acts further comprise determining to initiate the backend polling subscription having the timeout equal to zero based on a characteristic of the client device, the characteristic including one or more of a manufacturer of the client device, a model number of the client device, and an operating system of the client device. 
     
     
         17 . The non-transitory computer-readable media of  claim 14 , wherein the acts further comprise:
 monitoring client device behavior during a plurality of SIP subscription sessions; and   determining to initiate the backend polling subscription having the other timeout equal to zero based on the client device behavior.   
     
     
         18 . The non-transitory computer-readable media of  claim 17 , wherein the client device behavior includes:
 the client device receiving initial state information obtained from the backend server via prior persistent backend subscription sessions established previous to the backend polling subscription; and   the client device ignoring updates to the initial state information obtained from the backend server via the prior persistent backend subscription sessions.   
     
     
         19 . The non-transitory computer-readable media of  claim 14 , wherein the request indicates a request for at least one of capability or presence information for one or more contacts, and wherein the state information includes the at least one of capability or presence information for one or more contacts. 
     
     
         20 . The non-transitory computer-readable media of  claim 14 , wherein the client device includes a Rich Communication Services (RCS) client.