Session initiation protocol (SIP) dialog reconstruction through reconstruction anchors for user agents
Embodiments of the disclosure are directed to a call reconstruction server. This server can act as a signaling anchor for various SIP UAs involved in the session and can be included in the signaling path between UAs. More specifically, the reconstruction server can insert an identifier such as a Uniform Resource Identifier (URI) into the headers of SIP signaling messages exchanged between UAs during initiation of a session such as a call or conference. These identifiers can be used to insert the reconstruction servers into the path of the session in a way that “bookends” the other servers and/or processes in the session between the UAs. When one of these servers and/or processes restarts, the reconstruction servers can initiate a reconstruction process that rebuilds the session without relying on specially adapted UAs.
1. A system comprising:
a communication network; and
a reconstruction server coupled with the communication network, the reconstruction server comprising a processor and a memory, the memory comprising a set of instructions stored therein which, when executed by the processor, causes the processor to:
initiate a Session Initiation Protocol (SIP) dialog with a user agent on the communication network, wherein the user agent participates in the SIP dialog with a terminating endpoint on the communication network and a server providing one or more features to the SIP dialog, and wherein the reconstruction server provides a reconstruction anchor for the user agent in the SIP dialog during initiation of a session by receiving a SIP INVITE message; adding an identifier for the reconstruction anchor for the user agent to a header of the SIP INVITE message, and forwarding the SIP INVITE message to the terminating endpoint;
during the session, detect a restart of the server providing the one or more features to the SIP dialog; and
reconstruct the SIP dialog between the server providing the one or more features and the user agent.
2. The system of claim 1 , wherein the SIP dialog comprises a call between the user agent and the terminating endpoint.
3. The system of claim 2 , wherein initiating the SIP dialog further comprises:
receiving, at the reconstruction anchor for the user agent from a reconstruction server for the terminating endpoint, a SIP 200 OK message comprising an identifier for the reconstruction anchor for the terminating endpoint in a header of the SIP 200 OK message;
storing the identifier for the reconstruction anchor for the terminating endpoint;
associating the stored identifier for the reconstruction anchor for the terminating endpoint with the call; and
forwarding the SIP 200 OK message to the user agent.
4. The system of claim 3 , wherein the reconstruction server for the terminating endpoint receives the SIP INVITE message from the reconstruction server for the user agent, stores the identifier for the reconstruction anchor for the user agent, associates the stored identifier for the reconstruction anchor for the user agent with the call, forwards the SIP INVITE message to the terminating endpoint, receives the SIP 200 OK message from the terminating endpoint, adds the identifier for the reconstruction anchor for the terminating endpoint to the header of the SIP 200 OK message, and forwards the SIP 200 OK message to the reconstruction anchor for the user agent.
5. The system of claim 2 , wherein reconstructing the SIP dialog comprises:
receiving a SIP 481 NOT FOUND message from the server providing the one or more features to the SIP dialog;
sending a SIP 491 REQUEST PENDING message to the user agent;
sending, after the restart of the server providing the one or more features to the SIP dialog, a SIP in-dialog REFER message to the user agent;
receiving a SIP INVITE for a new SIP dialog from the user agent;
initiating the new SIP dialog via the reconstruction anchor for the user agent and a reconstruction anchor for the terminating endpoint, the new SIP dialog replacing the original SIP dialog.
6. The system of claim 1 , wherein the SIP dialog comprises a conference and the system further comprises a conference controller.
7. The system of claim 6 , wherein initiating the SIP dialog comprises:
receiving the SIP INVITE message from the user agent;
adding the identifier for the reconstruction anchor for the user agent to the header of the SIP INVITE message;
forwarding the SIP INVITE message to the conference controller;
receiving, at the reconstruction anchor for the user agent from the conference controller, a SIP 200 OK message; and
forwarding the SIP 200 OK message to the user agent.
8. The system of claim 7 , wherein the conference controller receives the SIP INVITE message from the reconstruction server for the user agent, stores the identifier for the reconstruction anchor for the user agent, associates the stored identifier for the reconstruction anchor for the user agent with the conference, initiates the conference with a media gateway, and sends the SIP 200 OK message to the reconstruction anchor for the user agent.
9. The system of claim 8 , wherein reconstructing the SIP dialog comprises:
receiving an out-of-dialog SIP REFER message from the conference controller following a restart of the conference controller;
sending an in-dialog SIP REFER message to the user agent;
receiving a SIP INVITE for a new SIP dialog from the user agent;
initiating the new SIP dialog via the reconstruction anchor for the user agent and the conference controller, the new SIP dialog replacing the original SIP dialog.
10. A method for reconstructing a communication session, the method comprising:
initiating, by a reconstruction server for a user agent, a Session Initiation Protocol (SIP) dialog with the user agent on a communication network, wherein the user agent participates in the SIP dialog with a terminating endpoint on the communication network and wherein the reconstruction server for the user agent provides a reconstruction anchor for the user agent in the SIP dialog by exchanging an identifier for the reconstruction anchor for the user agent via a SIP INVITE message;
detecting, by the reconstruction server for the user agent, a restart of a server providing one or more features to the SIP dialog; and
reconstructing, by the reconstruction server for the user agent, the SIP dialog between the user agent and the terminating endpoint using the reconstruction anchor, wherein reconstructing the SIP dialog comprises:
receiving, by the reconstruction server for the user agent, a SIP 481 NOT FOUND message from the server providing the one or more features to the SIP dialog;
sending, by the reconstruction server for the user agent, a SIP 491 REQUEST PENDING message to the user agent;
sending, by the reconstruction server for the user agent after the restart of the server providing the one or more features to the SIP dialog, a SIP in-dialog REFER message to the user agent;
receiving, by the reconstruction server for the user agent, a SIP INVITE for a new SIP dialog from the user agent; and
initiating, by the reconstruction server for the user agent, the new SIP dialog via the reconstruction anchor for the user agent and a reconstruction anchor for the terminating endpoint, the new SIP dialog replacing the original SIP dialog.
11. The method of claim 10 , wherein the SIP dialog comprises a call between the user agent and the terminating endpoint and wherein initiating the SIP dialog comprises exchanging identifiers for the reconstruction anchors between the reconstruction servers via SIP INVITE and SIP OK messages.
12. The method of claim 11 , wherein reconstructing the SIP dialog comprises:
receiving, by the reconstruction server for the terminating endpoint, a SIP 481 NOT FOUND message from the server providing the one or more features to the SIP dialog;
sending, by the reconstruction server for the terminating endpoint, a SIP 491 REQUEST PENDING message to the terminating endpoint;
sending, by the reconstruction server for the terminating endpoint, an out-of-dialog SIP REFER message to the reconstruction anchor for the user agent;
receiving, by the reconstruction server for user agent at the reconstruction anchor, the out-of-dialog SIP REFER message;
sending, by the reconstruction server for the user agent after the restart of the server providing the one or more features to the SIP dialog, a SIP in-dialog REFER message to the user agent;
receiving, by the reconstruction server for the user agent, a SIP INVITE for a new SIP dialog from the user agent; and
initiating, by the reconstruction server for the user agent, the new SIP dialog via the reconstruction anchor for the user agent and the reconstruction anchor for the terminating endpoint, the new SIP dialog replacing the original SIP dialog.
13. The method of claim 10 , wherein the SIP dialog comprises a conference and wherein initiating the SIP dialog comprises exchanging identifiers for the reconstruction anchors between the reconstruction servers via SIP INVITE and SIP OK messages.
14. The method of claim 13 , wherein reconstructing the SIP dialog comprises:
receiving, by the reconstruction server for the user agent, an out-of-dialog SIP REFER message from a conference controller following a restart of the conference controller;
sending, by the reconstruction server for the user agent, an in-dialog SIP REFER message to the user agent;
receiving, by the reconstruction server for the user agent, a SIP INVITE for a new SIP dialog from the user agent;
initiating, by the reconstruction server for the user agent, the new SIP dialog via the reconstruction anchor for the user agent and the reconstruction anchor for the one or more other endpoints, the new SIP dialog replacing the original SIP dialog.
15. A computer-readable device comprising a set of instructions stored therein which, when executed by a processor, causes the processor to reconstruct a communication session by:
initiating, by a reconstruction server for a user agent, a Session Initiation Protocol (SIP) dialog with the user agent on a communication network, wherein the user agent participates in the SIP dialog with a terminating endpoint and a server providing one or more features to the SIP dialog on the communication network and wherein the reconstruction server for the user agent provides a reconstruction anchor for the user agent in the SIP dialog during initiation of the communication session by receiving a SIP INVITE message; adding an identifier for the reconstruction anchor for the user agent to a header of the SIP INVITE message, and forwarding the SIP INVITE message to the terminating endpoint;
detecting, by the reconstruction server for the user agent, a restart of the server providing the one or more features to the SIP dialog; and
reconstructing, by the reconstruction server for the user agent, the SIP dialog between the user agent and the server providing the one or more features.
16. The computer-readable device of claim 15 , wherein the SIP dialog comprises a call between the user agent and the terminating endpoint and wherein initiating the SIP dialog comprises exchanging identifiers for reconstruction anchors between reconstruction servers via SIP INVITE and SIP OK messages.
17. The computer-readable device of claim 16 , wherein reconstructing the SIP dialog comprises:
receiving, by the reconstruction server for the user agent, a SIP 481 NOT FOUND message from the server providing the one or more features to the SIP dialog;
sending, by the reconstruction server for the user agent, a SIP 491 REQUEST PENDING message to the user agent;
sending, by the reconstruction server for the user agent after the restart of the server providing the one or more features to the SIP dialog, a SIP in-dialog REFER message to the user agent;
receiving, by the reconstruction server for the user agent, a SIP INVITE for a new SIP dialog from the user agent; and
initiating, by the reconstruction server for the user agent, the new SIP dialog with the server providing the one or more features via the reconstruction anchor for the user agent, the new SIP dialog replacing the original SIP dialog.
18. The computer-readable device of claim 15 , wherein the SIP dialog comprises a conference and wherein initiating the SIP dialog comprises exchanging identifiers for reconstruction anchors between reconstruction servers via SIP INVITE and SIP OK messages.
19. The computer-readable device of claim 18 , wherein reconstructing the SIP dialog comprises:
receiving, by the reconstruction server for the user agent, an out-of-dialog SIP REFER message from a conference controller following a restart of the conference controller;
sending, by the reconstruction server for the user agent, an in-dialog SIP REFER message to the user agent;
receiving, by the reconstruction server for the user agent, a SIP INVITE for a new SIP dialog from the user agent;
initiating, by the reconstruction server for the user agent, the new SIP dialog with the conference controller via the reconstruction anchor for the user agent, the new SIP dialog replacing the original SIP dialog.