Early offer not working when making external calls via expressway

[carl_townshend]

Hi All

When making external calls, we are not seeing the SDP information on the invite message, the calls with devices on the cucm send the sdp, but when making external calls going via our expressway c and e, I cannot see the sdp part of the invite.

It looks like early offer is not working, any ideas where I need to check for this ?

cheers

[Jonathan Schulenberg]

SIP Profile of the egress SIP trunk. It should be Early Offer = Best Effort.

[carl_townshend]

Hi Jonathan

Thanks for the response, I have done packet captures from VC > CUCM and from CUCM > EXP-C , I can see on both legs that the SDP and BFCP info is indeed being sent out, we even receive the 200 ACK message from Pexip on the invite which also contains the SDP info etc.

Based on this, I am guessing the issue is with Pexip.

Regarding the screen sharing issue we have, I have found something on the Cisco website that says "all endpoints that require BFCP support must be SIP, a teams call joining the pexip session to me isn't SIP.

What are your thoughts?

Cheers

[Jonathan Schulenberg]

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a teams call joining the pexip session to me isn't SIP.

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CUCM and Expressway only support H.323 and SIP; BFCP is specific to SIP. You didn't link to the source of that quote but it was likely a reference to H.323 which used H.239 for content sharing. If the call is connecting to Pexip using H.323, that's your problem. If not, worth grabbing a diagnostic log from Expressway-E as well to confirm the SDP exchange with Pexip directly.

[b.winter]

Hi, apart from what @Jonathan Schulenberg, what's the problem with delayed offer? Both methods are correct, so I don't see a problem in your question...

[carl_townshend · Accepted solution]

This has now been resolved, it was a service desk training issue. Basically you have to click make presenter to the Cisco VC from the teams call, it then allows the Cisco VC to share content I.e a plugged in pc screen share. Nice and simple in the end.