Cisco Cisco TelePresence Video Communication Server Expressway
Appendix 4 – Known interoperating limitations
Appendix 4 – Known interoperating limitations
Video codecs
If MOC (Microsoft Office Communicator) is used, then the video endpoints registered to the Cisco
VCS Control must support H.263; this is the common video codec supported by endpoints and the
MOC client. (The MOC client does not support H.264.)
VCS Control must support H.263; this is the common video codec supported by endpoints and the
MOC client. (The MOC client does not support H.264.)
Video codec selection
When the Cisco VCS Control receives an H.323 call destined for OCS, the Cisco VCS must interwork
the call to SIP and generate a SIP INVITE to send to the OCS. OCS does not support INVITES with
no SDP – in other words, without a list of codecs that can be used for the call, so the Cisco VCS
Control must populate the SDP with a “pre-chosen” list of codecs from which the OCS can select.
the call to SIP and generate a SIP INVITE to send to the OCS. OCS does not support INVITES with
no SDP – in other words, without a list of codecs that can be used for the call, so the Cisco VCS
Control must populate the SDP with a “pre-chosen” list of codecs from which the OCS can select.
The codecs offered and selected, therefore, may not reflect the best codecs that could have been
selected by the endpoints.
selected by the endpoints.
Joining a MOC conference (AV MCU)
Using a MOC client to invite a third party to join the call does not work whether the third endpoint is the
endpoint registered to the Cisco VCS Control or whether the endpoint registered to the Cisco VCS
Control is already in the call and another MOC client is introduced into the call.
endpoint registered to the Cisco VCS Control or whether the endpoint registered to the Cisco VCS
Control is already in the call and another MOC client is introduced into the call.
This is because when the MOC client invites a third party to join a call, the MOC client tries to create a
conference using Microsoft proprietary messaging (xml in SIP messages), and this is not supported by
standards-based video endpoints.
conference using Microsoft proprietary messaging (xml in SIP messages), and this is not supported by
standards-based video endpoints.
Neither Cisco VCS Control nor standards-based video endpoints support the Microsoft proprietary
signaling.
Note, however use of Multiway™ on endpoints can join MOC clients into an ad hoc conference. See
the Cisco VCS Multiway™ deployment guide.
signaling.
Note, however use of Multiway™ on endpoints can join MOC clients into an ad hoc conference. See
the Cisco VCS Multiway™ deployment guide.
Up-speeding from a voice call to a video call
Interworking a MOC client to an H.323 endpoint, the call will only up-speed from voice to video if the
up-speed request occurs before the endpoint sends a BRQ lowering the connection bandwidth.
up-speed request occurs before the endpoint sends a BRQ lowering the connection bandwidth.
MOC accessing OCS through Microsoft Edge Server
When MOC registers to OCS through a Microsoft Edge Server, the sdp from MOC contains Microsoft
ICE candidates, and the non local candidate needs to be used.
ICE candidates, and the non local candidate needs to be used.
This functionality is not supported in Cisco VCS X5. Calls made from an endpoint registered to Cisco
VCS to MOC should work, but calls made from MOC to an endpoint registered to Cisco VCS are likely
to result in audio and video on the endpoint registered to Cisco VCS, but no video or audio on MOC.
VCS to MOC should work, but calls made from MOC to an endpoint registered to Cisco VCS are likely
to result in audio and video on the endpoint registered to Cisco VCS, but no video or audio on MOC.
Cisco VCS Deployment Guide: Microsoft OCS 2007 R1 and R2 and Cisco VCS X5.2
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