SIP Trunk Timeout Value Adjustment

[Michael Mertens]

So I have two SIP trunks (going to two Derdack Enterprise Alert Managers) that are part of a Route Group. It seems when the VoIP Service is turned-down (testing fail-over), CUCM doesn't declare the trunk down for 60 seconds. I looked through the CUCM Service Parameters > SIP Trunk but didn't notice any current value that seemed to match a SIP/TCP trunk keep-alive timer. Can any point me to what the parameter is on CUCM that may control the length of time that a SIP trunk needs to be down, before it is pulled out of a RG rotation?

THANKS!

Mike,

[gogasca · Accepted solution]

Hi Michael,

Let me clarify 2 main differences here:

1. We support SIP OPTIONS in 8.5 and above, which act as a Keepalive and this link describe the parameters

needed to tweak the default values.

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/rel_notes/8_5_1/delta/delta.html#wp1820323

2. Without SIP OPTIONS,  we dont declare SIP Trunk or Down, nor we monitor the SIP trunk,

CUCM has two Steps to check the connectivity with the remote sip party through tcp:

Step 1:  checking the TCP sync "sip tcp timer"

- if failed: meaning the timer expired before getting tcp ACK then this session will be

torn down and cm will select the secondary device in the corresponding route group if

exist.

- if the tcp passed: meaning we got tcp ACK before this timer expires then cm will send

Invite message and starts step 2

Step 2:  checking "the sip invte expires timer"

- as soon as cm sends Invite message this timer will start and if expired before receiving

ACK on the invite message, cm will retry the same according to the configured count number

of "Retry INVITE"

HTH

[Michael Mertens]

Thanks for the help and detailed answer!