Cisco Cisco TelePresence Video Communication Server Expressway
l
David’s internal video endpoint with an alias of david.jones.office@vc.ciscotp.com
l
David’s home office video endpoint with an alias of david.jones.external@vc.ciscotp.com
n
Lync Front End Server is configured with a static domain route which routes URIs with the VCS's video
network domain (vc.ciscotp.com) to the VCS. Care must be taken when using domain static routes; any
traffic for that domain that Lync cannot handle locally will be routed to VCS.
network domain (vc.ciscotp.com) to the VCS. Care must be taken when using domain static routes; any
traffic for that domain that Lync cannot handle locally will be routed to VCS.
n
MCUs that will receive calls from Lync can register conferences to the video network with a dedicated
MCU domain (mcu.ciscotp.com) and make these available to Lync users via a static SIP domain route
from the Lync environment (suitable for ad-hoc conference aliases). A separate domain for MCU
registrations is recommended as it more easily allows you to prevent SIP traffic coming from Lync via a
static route from propagating further into the video network than needed (by using search rules).
MCU domain (mcu.ciscotp.com) and make these available to Lync users via a static SIP domain route
from the Lync environment (suitable for ad-hoc conference aliases). A separate domain for MCU
registrations is recommended as it more easily allows you to prevent SIP traffic coming from Lync via a
static route from propagating further into the video network than needed (by using search rules).
n
The Presence Server residing on the VCS Control publishes presence information into the Lync
environment via the B2BUA application on the Lync gateway VCS. This Presence Server must be
authoritative for the video domain (vc.ciscotp.com) and any dedicated MCU domains (mcu.ciscotp.com) in
use.
environment via the B2BUA application on the Lync gateway VCS. This Presence Server must be
authoritative for the video domain (vc.ciscotp.com) and any dedicated MCU domains (mcu.ciscotp.com) in
use.
Clustered “Lync gateway” VCS
When this document refers to a “Lync gateway” VCS, a cluster of VCSs can also be used. The operation is
functionally the same, but there is more capacity available.
functionally the same, but there is more capacity available.
Calls from Lync Server will typically arrive at a single VCS in the cluster, as Lync Server will use the static
domain routes, which has a single IP address for TCP connectivity and a single FQDN for TLS connectivity.
domain routes, which has a single IP address for TCP connectivity and a single FQDN for TLS connectivity.
If using TLS and round-robin DNS for static route destinations, Lync Server may change the VCS peer that it
sends calls to, but only at a maximum rate of change of once per 5 seconds. Lync appears to keep sending
all traffic to one VCS unless it loses connection to that VCS, and only then does it swap to another VCS – so
this provides resilience rather than load balancing.
sends calls to, but only at a maximum rate of change of once per 5 seconds. Lync appears to keep sending
all traffic to one VCS unless it loses connection to that VCS, and only then does it swap to another VCS – so
this provides resilience rather than load balancing.
Why add a “Lync gateway” VCS?
The “Lync gateway” VCS is an interface between an existing working video network and the Microsoft Lync
environment. Using this gateway minimizes the changes that need to be made in the video network so as to
introduce as few artifacts as possible when adding Lync interoperability to the video network.
environment. Using this gateway minimizes the changes that need to be made in the video network so as to
introduce as few artifacts as possible when adding Lync interoperability to the video network.
Having dedicated VCSs for this “Lync gateway” operation limits the number of VCSs for which the Microsoft
Interoperability option key needs to be purchased and enabled.
Interoperability option key needs to be purchased and enabled.
Lync Server can only send calls to a single FQDN (though this may have a round robin DNS address to
support a cluster of VCSs for resilience) for calls via a static domain route defined in Lync Server.
support a cluster of VCSs for resilience) for calls via a static domain route defined in Lync Server.
Lync Server will only accept messages received from peers that it has been configured to trust. Having a
dedicated “Lync gateway” VCS or VCS cluster also limits the number of trusted devices that need to be
configured in Lync, as every device that sends SIP messages to Lync Server needs to be explicitly listed as
a trusted host in Lync Server.
dedicated “Lync gateway” VCS or VCS cluster also limits the number of trusted devices that need to be
configured in Lync, as every device that sends SIP messages to Lync Server needs to be explicitly listed as
a trusted host in Lync Server.
Multiple “Lync gateway” VCSs per Lync domain
Apart from when the VCSs are in a single “Lync gateway” cluster, this is not a recommended architecture as
calls from one video endpoint to another video endpoint that is called via its Lync domain will get routed via
Lync rather than directly through the video infrastructure; this will cause users to lose video functionality such
as duo video and far end camera control, and also possibly lose encryption and video quality.
calls from one video endpoint to another video endpoint that is called via its Lync domain will get routed via
Lync rather than directly through the video infrastructure; this will cause users to lose video functionality such
as duo video and far end camera control, and also possibly lose encryption and video quality.
Cisco TelePresence Microsoft Lync and Cisco VCS Deployment Guide (X8.2)
Page 7 of 80
Introduction