Using Webex Teams client to call video codec from Polycom or Cisco

[reddsman]

We have been trying to use Webex Teams to make SIP video calls to both Polycom and Cisco video endpoints such as Cisco DX-80s and Polycom Realpresence Group Series 500. All endpoints are registered to an Expressway-C on version 12.5.9. Firewall traversal is handled by an Expressway-E also at version 12.5.9. The Expressways are not connected to CUCM.

We have just started using Webex Teams to make calls directly to endpoints and have noticed the following. When the Webex Teams client calls a Cisco endpoint such as a DX-80 or Room Kit, the call is fine with no issues and will last longer than 15 minutes. However, when the Webex Teams client tries to call a Polycom endpoint, the call automatically disconnects after 15 minutes and between 20-41 seconds regardless of whether the call is still in session. Any calls to virtual meetings such as Webex meetings from any endpoint whether Cisco or Poly were able to remain connected with no timeout issues. We ran diagnostic logging on the both the Expressway-C and Expressway-E. On the Expressway-E we noticed that the Polycom devices were sending out an update packet to which it received no reply and then disconnected the call. The Cisco endpoint sent out an invite packet to which it did receive a reply and acknowledgement. I noticed that on the Expressways there is a setting in the different zones that says SIP Update for session refresh that is off. For this issue, is that a setting we should turn on?

[Ayodeji Okanlawon]

This is a session refresh issue and it appears that the polycom devices are using UPDATE. I would try turning it on and test to see if it fixes it but also I would check what impact it has on other endpoints as well. I also doubt if this will work because because this feature is only supported for MRA and not for B2B calls.

Here is an excerpt on the documentation:

MRA: SIP Update Method Support for Session Refresh From X12.5, the Cisco Expressway Series supports the SIP UPDATE method over MRA connections for session refresh purposes only. That is, to send and receive session timers for a periodic session refresh (RFC 4028).

SIP UPDATE for session refresh is not supported for Business-to-Business deployments.

CAUTION: Do not enable this method unless it is absolutely necessary.

Only enable SIP UPDATE for session refresh if RE-INVITE based session refresh has issues between Expressway-C and Unified CM. Expressway uses the re-INVITE method for session refresh by default.

To use the SIP UPDATE method, the SIP UPDATE for session refresh setting must be enabled on the zones that traverse SIP signaling (Configuration > Zones > Zones). To configure SIP UPDATE as a preferred method for zones that are auto-generated, enable the SIP UPDATE for the session refresh setting when you discover each Unified CM node (Configuration > Unified Communications > Unified CM Servers). SIP UPDATE for session refresh support over MRA has some limitations. For example, the following features that rely on the SIP UPDATE method (RFC 3311) will fail:

■ Request to display the security icon on MRA endpoints for end-to-end secure calls.

■ Request to change the caller ID to display name or number on MRA endpoints.

From this document

https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/release_note/Cisco-Expressway-Release-Note-X12-5-6.pdf