This document covers the information about SIP Session Timer support and the configuration procedure on Cisco Unified Border Element (CUBE).
About SIP Session Timer support on CUBE
The SIP Session Timer Support feature adds the capability to periodically refresh Session Initiation Protocol (SIP) sessions by sending repeated INVITE requests. The repeated INVITE requests, or re-INVITEs, are sent during an active call leg to allow user agents (UAs) or proxies to determine the status of a SIP session. Without this keepalive mechanism, proxies that remember incoming and outgoing requests (stateful proxies) may continue to retain the call state needlessly. If a UA fails to send a BYE message at the end of a session or if the BYE message is lost because of network problems, a stateful proxy does not know that the session has ended. The re-INVITES ensure that active sessions stay active and completed sessions are terminated.
1. Cisco Unified Border Element
Cisco IOS Release 12.2(8)T or a later release must be installed and running on your Cisco Unified Border Element.
2. Cisco Unified Border Element (Enterprise)
Cisco IOS XE Release 2.5 or a later release must be installed and running on your Cisco ASR 1000 Series Router..
Interoperability- This feature provides a periodic refresh of SIP sessions. The periodic refresh allows user agents and proxies to monitor the status of a SIP session, preventing hung network resources from pausing indefinitely when network failures occur.
How to configure SIP Session Timer support ?
Ensure that the gateway has voice functionality that is configurable for SIP.
Establish a working IP network.
2. configure terminal
3. voice service voip
5. min-se seconds
6. min-se exit
7. min-se show sip-ua min-se
This example contains partial output from the show running-configcommand. It shows that the Min-SE value has been changed from its default value.
voice service voip
Because of the processing load of INVITE requests you can configure a minimum timer value that the proxy, UAC, and UAS can accept. The proxy, UAC, and UAS. The min-secommand sets the minimum timer, and it is conveyed in the Min-SE header in the initial INVITE request.
When making a call, the presence of the Min-SE header informs the UAS and any proxies of the minimum value that the UAC accepts for the session timer duration, in seconds. The default value is 1800 seconds (30 minutes). By not reducing the session timer below the value set, the UAS and proxies prevent the UAC from having to reject a call with a 422 error. Once set, the min-se command value affects all calls originated by the router. If the Min-SE header is not present, the UA accepts any value.
The syntax of the Min-SE header is:
Min-SE = "Min-SE" ":" delta-seconds
To troubleshoot this feature, perform the following steps:
Make sure that you can make a voice call.
Use the debug ccsip all command to enable all SIP debugging capabilities, or use one of the following SIP debug commands: