Avaya Support Forums - CM8.1 SIP Trunk to Session Manager keep alive

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In case the L3 testing is enabled on the SIP sig-group page, the CM will do a SIP OPTION message exchange for testing the trunk’s state. Test 1675 is performed by CM periodically, and it may take up to 15 minutes for the test to be run again on the same trunk related signaling group. If this testing fails, CM will further move on and report the trunk state/alarm (warning by default based on the “set options” screens – can be done by Avaya init or inads login only). Even though the CM can realize a TCP socket down (denial 2094), this is not in direct connection with the test 1675. The test 1675 has to fail, to see a “IP SIG-GRP xyz IS BYPASS” message in the logs, to look further for any CM alarms.

If there are calls over the SIP trunk, and calls are failing to establish, then maintenance will be notified and the test will be performed earlier than the scheduled maintenance testing. This will cause the signaling group to be placed in bypass much more quickly. Sending of SIP OPTION message is triggered by periodic maintenance, which happens every 15 minutes (not adjustable) and it take 32 second after that to determine that the far end is not responding. This is in case of the IDLE scenario when there is no other traffic. If there is traffic on the signaling/trunk group (calls traversing), then after some call failure the CM will forcefully run the test and determine the signaling group’s state.