Cisco Cisco TelePresence Video Communication Server Expressway
Appendix 2: Known Interworking Capabilities and Limitations
Capabilities
SIP and H.323 Endpoints Making Basic Calls
■
SIP and H.323 endpoints can make calls via the VCS to endpoints registered to Unified CM.
■
Endpoints registered to Unified CM can make calls to SIP and H.323 endpoints on the VCS.
Limitations
Cisco TelePresence Conductor
When VCS is configured to work with TelePresence Conductor, calls made from Unified CM over the SIP trunk may
initiate or join conferences controlled by TelePresence Conductor. When there is a Cisco TelePresence System
(CTS) Series endpoint registered to the Unified CM, the VCS is connected to the TelePresence Conductor’s back-to-
back user agent and the conference is hosted on a TelePresence Server, encrypted calls made from the CTS will
drop when the SIP session is refreshed. In this scenario we recommend that you create a SIP trunk directly from the
Unified CM to the TelePresence Conductor as detailed in
initiate or join conferences controlled by TelePresence Conductor. When there is a Cisco TelePresence System
(CTS) Series endpoint registered to the Unified CM, the VCS is connected to the TelePresence Conductor’s back-to-
back user agent and the conference is hosted on a TelePresence Server, encrypted calls made from the CTS will
drop when the SIP session is refreshed. In this scenario we recommend that you create a SIP trunk directly from the
Unified CM to the TelePresence Conductor as detailed in
E20 Encryption
If E20 has Encryption Mode = Best Effort then calls from Unified CM clear when E20 answers them. Set Encryption
Mode = Off.
Mode = Off.
T150 Running L6.0 Code
If a SIP call is made from a T150 running L6.0 code to Unified CM 8.0 (and earlier), Unified CM does not handle the
UPDATE message that the T150 sends immediately after the call is answered, and so on call answer the call is
cleared down immediately.
UPDATE message that the T150 sends immediately after the call is answered, and so on call answer the call is
cleared down immediately.
If
xConfiguration Conference H239
is set to Off then no BFCP is offered and Unified CM handles the UPDATE from the
T150 and the call completes as desired.
H.323 MXP and 9971
When an MXP registered to VCS is in a call with a 9971 registered to Unified CM and the MXP call is H.323, the video
on the MXP will be CIF (small picture) rather than VGA (full size picture). (Seen on MXP F9.0 and 9971 version 9.0.2)
on the MXP will be CIF (small picture) rather than VGA (full size picture). (Seen on MXP F9.0 and 9971 version 9.0.2)
If the MXP call is SIP, a full size picture will be seen.
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Cisco VCS SIP Trunk to Unified CM Deployment Guide