Conference reconstruction in SIP networks
During a Session Initiation Protocol dialog setup, the user agent sends an INVITE message with an SDP offer to the conference controller, and the conference controller provides to a media gateway a unique session identifier, a unique conference identifier, and optionally at least one of feature information and/or policy information. If the conference controller restarts, the media gateway may provide the conference controller the unique session identifier, the unique conference identifier, and the optional feature and/or policy information. The conference controller may then generate an out-of-dialog SIP REFER message that includes the unique session identifier and the unique conference identifier and provide the message to the user agent. The user agent, upon receiving the REFER message, may identify a dialog needing replacing, and may provide the conference controller a new INVITE message that allows the conference controller to reconstruct the SIP dialog and optional feature and/or policy information if needed.
1. A method of managing a Session Initiation Protocol (SIP) dialog between a network element and a conference controller during a SIP conference call, the method comprising:
sending, by the network element, a first INVITE message to the conference controller, the first INVITE message including a session description protocol (SDP) offer;
establishing a first SIP dialog between the network element and the conference controller;
in response to a signaling-disrupting event having occurred during the SIP conference call, sending, by the network element, a second INVITE message to the conference controller, the second INVITE message including the same SDP offer as the first INVITE message; and
establishing a second SIP dialog between the network element and the conference controller before terminating the first SIP dialog.
2. The method according to claim 1 , wherein establishing the second SIP dialog between the network element and the conference controller includes:
receiving, at the network element, an out-of-dialog SIP REFER message including a Request-URI header, the Request-URI header including a unique conference identifier; and
sending, by the network element, the second INVITE message to a device associated with the unique conference identifier.
3. The method according to claim 2 , further comprising:
receiving, at the network element, a unique session identifier;
identifying a dialog based on the unique session identifier; and
terminating the identified dialog.
4. The method according to claim 3 , wherein the identified dialog is for a call that is in a connection preserved state for the SIP conference call.
5. The method according to claim 1 , further comprising:
receiving, at the conference controller, a unique session identifier and a unique conference identifier; and
generating, by the conference controller, a SIP REFER message including the unique session identifier and the unique conference identifier.
6. The method according to claim 5 , wherein the unique session identifier and the unique conference identifier are received in response to determining that the signaling-disrupting event has occurred during the SIP conference call.
7. The method according to claim 1 , further comprising:
receiving, at a media gateway, a unique session identifier per ephemeral termination, wherein at least one media path is active between the media gateway and the network element.
8. The method according to claim 7 , further comprising:
receiving, at the media gateway, a unique conference identifier; and
associating the unique session identifier and the unique conference identifier to an ephemeral termination.
9. The method according to claim 8 , wherein when the SIP conference call spans multiple media gateways, the unique conference identifier is provided to all terminations for the SIP conference call on each one of the multiple media gateways.
10. The method according to claim 8 , further comprising:
providing the unique conference identifier, the unique session identifier, and a plurality of contexts within the media gateway having the unique conference identifier and the unique session identifier to the conference controller.
11. The method according to claim 10 , further comprising:
receiving, at the media gateway, at least one of feature information and policy information; and
providing the at least one of feature information and policy information to the conference controller.
12. The method according to claim 1 , further comprising:
receiving, at the conference controller, the first INVITE message from the network element, the first INVITE message including the session description protocol (SDP) offer;
generating a unique session identifier and a unique conference identifier;
providing the unique session identifier and the unique conference identifier to a media gateway, wherein at least one media path is active between the media gateway and the network element;
receiving, at the conference controller, the unique session identifier and the unique conference identifier in response to the signaling-disrupting event having occurred during the SIP conference call; and
generating, by the conference controller, an out-of-dialog SIP REFER message including a Request-URI header, the Request-URI header including the unique conference identifier.
13. The method according to claim 1 , wherein an existing media path associated with the first SIP dialog between the network element and a media gateway is maintained when the second SIP dialog is established.
14. A system comprising:
a network element including:
a processor; and
memory including one or more instructions that when executed by the processor, enable the network element to:
send a first INVITE message to a conference controller, the first INVITE message including a session description protocol (SDP) offer;
establish a first SIP dialog between the network element and the conference controller;
in response to a signaling-disrupting event having occurred during a SIP conference call, send a second INVITE message to the conference controller, the second INVITE message including the same SDP offer as the first INVITE message; and
establish a second SIP dialog between the network element and the conference controller before terminating the first SIP dialog.
15. The system of claim 14 , wherein the network element includes a SIP user agent.
16. The system of claim 15 , wherein the network element is further configured to receive a SIP REFER message including a unique session identifier and a unique conference identifier in at least one header of the SIP REFER message.
17. The system according to claim 16 , wherein the unique session identifier and the unique conference identifier are received in response to determining that the signaling-disrupting event has occurred during the SIP conference call.
18. The system according to claim 14 , wherein the unique session ID is received per ephemeral termination for a media gateway.
19. A non-transitory computer readable medium having stored thereon instructions that cause a processor to execute a method, the instructions comprising:
one or more instructions to send, from a SIP user agent to a conference controller, a first INVITE message, the first INVITE message including a session description protocol (SDP) offer;
one or more instructions to establish a first Session Initiation Protocol (SIP) dialog between the SIP user agent and the conference controller;
one or more instructions to send, by the SIP user agent, a second INVITE message to the conference controller in response to a signaling-disrupting event having occurred during a SIP conference call, the second INVITE message including the same SDP offer as the first INVITE message; and
one or more instructions to establish a second SIP dialog between the SIP user agent and the conference controller before terminating the first SIP dialog.