Cisco Cisco TelePresence Video Communication Server Expressway
Joining a Lync conference (AV MCU)
Using a Lync client to invite a third party to join the call does not work if the third endpoint is an endpoint
registered to the VCS Control, or if the endpoint registered to the VCS Control is already in the call and
another Lync client is introduced into the call.
registered to the VCS Control, or if the endpoint registered to the VCS Control is already in the call and
another Lync client is introduced into the call.
This is because when the Lync client invites a third party to join a call, the Lync 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 VCS Control nor standards-based video endpoints support the Microsoft proprietary signaling. Note,
however use of Multiway on endpoints can join Lync clients into an ad hoc conference (see Cisco
TelePresence Multiway Deployment Guide).
however use of Multiway on endpoints can join Lync clients into an ad hoc conference (see Cisco
TelePresence Multiway Deployment Guide).
Upspeeding from a voice call to a video call
Interworking a Lync client to an H.323 endpoint, the call will only upspeed from voice to video if the upspeed
request occurs before the endpoint sends a BRQ lowering the connection bandwidth.
request occurs before the endpoint sends a BRQ lowering the connection bandwidth.
Microsoft Mediation Server
Calls to Microsoft Mediation Servers work from endpoints in the VCS video network for SIP initiated calls,
but do not work for interworked H.323 initiated calls (the mediation server does not respond to the VCS INFO
message, sent to check availability of the destination number).
but do not work for interworked H.323 initiated calls (the mediation server does not respond to the VCS INFO
message, sent to check availability of the destination number).
A workaround is possible if the format of the numbers that will be routed to the mediation server can be
configured in VCS.
configured in VCS.
The workaround is to send some calls through a different zone from the "Lync gateway" VCS to the
Lync Server, as follows:
Lync Server, as follows:
1. Create a new neighbor zone and select Custom in the Zone profile field.
3. Configure one or more search rules, with the correct priority, such that the appropriate subset of calls
destined for the Mediation Server are routed through the new zone rather than the standard "To Microsoft
Lync Server via B2BUA" zone.
Lync Server via B2BUA" zone.
4. You may also need to change the On successful match action from Stop to Continue on the search rule
.
Setting
Lync Server zone configuration
Monitor peer status
Yes
Call signaling routed mode
Auto
Automatically respond to H.323 searches
Off
Automatically respond to SIP searches
On
Send empty INVITE for interworked calls
Off
Table 1: Custom neighbor zone attributes to work around Mediation Server limitation
Cisco TelePresence Microsoft Lync and Cisco VCS Deployment Guide (X8.2)
Page 67 of 80
Appendix 4: Interoperating capabilities and limitations