Cisco Cisco TelePresence Video Communication Server Expressway
Appendix 2: Known interworking capabilities and
limitations
limitations
Capabilities
SIP and H.323 endpoints making basic calls
n
SIP and H.323 endpoints can make calls via the VCS to endpoints registered to Unified CM.
n
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
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
E20 encryption
If E20 has Encryption Mode = Best Effort then calls from Unified CM clear when E20 answers them. Set
Encryption Mode = Off.
Encryption 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.
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.
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.
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)
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)
If the MXP call is SIP, a full size picture will be seen.
Cisco Unified Communications Manager with Cisco VCS (SIP Trunk) Deployment Guide (X8.5)
Page 39 of 48
Appendix 2: Known interworking capabilities and limitations