Two-way call forwarding between voip system and pstn without call dead-circle

Abstract

System and method of two-way call forwarding between a Voice over IP (VoIP) system to a regular phone system without causing call dead-circle. A user's regular phone may be configured for automatic call forwarding to the VoIP system, e.g., to avoid roaming. At the same time, the user's VoIP account may also be configured for automatic call forwarding to the regular phone, e.g., to increase the chance that the user can be reached by a caller when the VoIP account is offline. The VoIP system can determine whether a call request is routed from the phone network (e.g., PSTN) of the regular phone or from the Internet. If it is from the phone network, the VoIP system tags the phone number and, if the VoIP account is currently offline, the VoIP system drops the call despite the call-forwarding configuration in the VoIP account.

What is claimed is: 
     
         1 . A computer implemented method of facilitating a real-time call session, said method comprising:
 receiving a call request at a Session Initiation Protocol (SIP) platform in a Voice over Internet Protocol (VoIP) system;   identifying a VoIP user account based on said call request, wherein an identification of said VoIP user account is same as a phone number controlled by a phone network that is external to said VoIP system, wherein said VoIP user account is configured for call forwarding to said phone number if said VoIP user account is offline;   determining a network that routes said call request to said SIP platform;   responsive to a determination that said network corresponds to said phone network, associating a status identifier with said VoIP user account, wherein said status identifier indicates that said call request is converted from an initial call request that is directed to said phone number through said phone network; and   responsive to a detection that said VoIP user account is currently offline and based on said status identifier, generating a message that a user associated with said phone number is unavailable without call forwarding to said phone number.   
     
     
         2 . The computer implemented method of  claim 1  further comprising, responsive to a detection that said VoIP user account is online, initiating a VoIP call session with said VoIP user account. 
     
     
         3 . The computer implemented method of  claim 1 , wherein a phone device of said phone number is configured to automatically forward call requests that are initially directed to said phone number to said VoIP system. 
     
     
         4 . The computer implemented method of  claim 1 , wherein said phone device of said phone number is configured to automatically forward call requests that are directed to said phone number to an access number of said SIP platform. 
     
     
         5 . The computer implemented method of  claim 4 , wherein said access number is a local phone number in a home region of said phone network. 
     
     
         6 . The computer implemented method of  claim 1 , wherein said associating a status identifier comprises adding a tag to said phone number in a call log maintained by said SIP platform. 
     
     
         7 . The computer implemented method of  claim 1 , wherein said phone network is Public Switched Telephone Network (PSTN). 
     
     
         8 . A system comprising:
 communication circuits;   a processor; and   memory coupled to said processor and comprising instructions that, when executed by said processor, cause the system to perform a method of facilitating voice communication over Voice over Internet Protocol (VoIP) system according to a Session Initiation Protocol (SIP), said method comprising:
 receiving a call request at a Session Initiation Protocol (SIP) platform; 
 identifying a VoIP user account based on said call request, wherein an identification of said VoIP user account is same as a phone number controlled by a phone network that is external to said VoIP system, wherein said VoIP user account is configured for call forwarding to said phone number if said VoIP user account is offline; 
 identifying a network that routes said call request to said SIP platform; 
 responsive to a determination that said network corresponds to said phone network, associating a status identifier with said phone number, wherein said status identifier indicates that said call request is converted from an initial call request that is directed to said phone number through said phone network; and 
 responsive to a detection that said VoIP user account is currently offline and based on said status identifier, generating a message that a user associated with said phone number is unavailable without call forwarding to said phone number. 
   
     
     
         9 . The system  claim 8 , wherein said method further comprises, responsive to a detection that said VoIP user account is online, initiating a VoIP call session with said VoIP user account. 
     
     
         10 . The  claim 8 , wherein a phone device of said phone number is configured to automatically forward call requests that are initially directed to said phone number to said VoIP system. 
     
     
         11 . The system  claim 8 , wherein said phone device of said phone number is configured to automatically forward call requests that are directed to said phone number to an access number of said SIP platform. 
     
     
         12 . The system  claim 11 , wherein said access number is a local phone number in a home region of said phone network. 
     
     
         13 . The system  claim 8 , wherein said associating a status identifier comprises tagging said phone number in a call log maintained by said SIP platform. 
     
     
         14 . The system  claim 8 , wherein said phone network is a wireless phone network. 
     
     
         15 . A Session Initiation Protocol (SIP) server of a Voice over Internet Protocol (VoIP) network comprising:
 communication circuits communicatively coupled to an external phone network that is external to said VoIP network;   a processor; and   memory coupled to said processor and comprising instructions that, when executed by said processor, cause the SIP server to perform a method comprising:
 receiving a call request; 
 identifying a VoIP user account based on said call request, wherein an identification of said VoIP user account is same as a phone number controlled by said external phone network, wherein said VoIP user account is configured for call forwarding to said phone number if said VoIP user account is offline; 
 identifying a network that routes said call request to said SIP platform; 
 if said network corresponds to said external phone network, associating a status identifier with said VoIP user account, wherein said status identifier indicates that said call request is converted from an initial call request that is directed to said phone number through said external phone network; and 
 responsive to a detection that said VoIP user account is currently offline and based on said status identifier, generating a message that a user associated with said phone number is unavailable without call forwarding to said phone number. 
   
     
     
         16 . The SIP server of  claim 15 , wherein said method further comprises, responsive to a detection that said VoIP user account is online, initiating a VoIP call session with said VoIP user account. 
     
     
         17 . The SIP server of  claim 15 , wherein a phone device of said phone number is configured to automatically forward call requests that are initially directed to said phone number to said VoIP system. 
     
     
         18 . The SIP server of  claim 15 , wherein a phone device of said phone number is configured to automatically forward call requests that are directed to said phone number to an access number of said SIP server. 
     
     
         19 . The SIP server of  claim 18 , wherein said access number is a local phone number in a home region of said phone network. 
     
     
         20 . The SIP server of  claim 15 , wherein said external phone network is a Public Switched Telephone Network (PSTN).