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does SIP recorder need to respond on 2nd invite (keep-alive?)


We build a call recorder that records via a SIP trunk through the phone's built in bridge which works fine until 16 min where the CUCM sends a BYE.

It had send a INVITE in the 15th minute, assuming this is a keep-alive? (our recorder ignores that message..)

Looking at Cisco's SIP documentation, I can't find keep-alive messages in call flows, once the call is up it should stay up until either party hangs up and a BYE is sent..

Has anyone seen this before or knows the exact message flow that should occur?

We can add a OK resonse or so on the 2nd INVITE, but only want to if that is required

Everyone's tags (3)
New Member

does SIP recorder need to respond on 2nd invite (keep-alive?)

Hi Sascha,

I encountered the same "problem". I can't find any documentation concerning SIP for the BIB except the few lines in the Cisco document "monitoring and recording".

I send a OK on every INVITE and that keeps the media streams alive.

I sended a private message to you, hope you can help me with that issue.


Cisco Employee

Re: does SIP recorder need to respond on 2nd invite (keep-alive?

Hi Sascha,

During this SIP conversation between the UAC and UAS, there is a decision which made who is going to refresh the session either UAC or UAS. Makesure is that is followed. If possible atttach the SIP Logs.

Also while the Re-Invite is sent, is there any change in media or SDP from the initial Invite

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