Cisco Cisco TelePresence Video Communication Server Expressway
Connecting multiple MCUs to a single Cisco VCS
Cisco VCS Deployment Guide: Connecting MCUs to Cisco VCSs for resilience and capacity
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Note: If any MCU is nearly full of callers (or has reached the limit of the number of conferences it can
handle) it reports “out of resources” to the Cisco VCS. The Cisco VCS will then adjust its
randomization algorithm to omit the nearly full MCU(s). The “out of resource” report will not affect the
routing of callers to existing conferences. In this way, callers to conferences that have already been
set up will continue to be sent to the appropriate MCU so that they can be in the same conference as
all others dialing that conference ID; new conferences will only be set up on MCUs that are not
reporting “out of resources”.
handle) it reports “out of resources” to the Cisco VCS. The Cisco VCS will then adjust its
randomization algorithm to omit the nearly full MCU(s). The “out of resource” report will not affect the
routing of callers to existing conferences. In this way, callers to conferences that have already been
set up will continue to be sent to the appropriate MCU so that they can be in the same conference as
all others dialing that conference ID; new conferences will only be set up on MCUs that are not
reporting “out of resources”.
For capacity and resilience, each MCU should register on Cisco VCS with a unique service prefix. For
example MCU1 would use prefix 81, MCU2 would use prefix 82, MCU3 would use prefix 83, and so
on. This is recommended for both clustered and non-clustered Cisco VCS deployments.
example MCU1 would use prefix 81, MCU2 would use prefix 82, MCU3 would use prefix 83, and so
on. This is recommended for both clustered and non-clustered Cisco VCS deployments.
Configuration
1. Configure each MCU to register identical service prefix(es) to the Cisco VCS.
2. Configure each MCU to register with a Gatekeeper registration type =MCU (standard),
configurable on the Settings > Gatekeeper page.
The Cisco VCS then handles all the conference call routing.
Note: The Gatekeeper registration type MUST NOT be Gateway because otherwise the Cisco
VCS will distribute calls to a specific conference ID randomly across all MCUs that have registered a
matching prefix. Only if Gatekeeper registration type is MCU will the Cisco VCS ensure that calls to
the same conference ID get routed to the same MCU.
VCS will distribute calls to a specific conference ID randomly across all MCUs that have registered a
matching prefix. Only if Gatekeeper registration type is MCU will the Cisco VCS ensure that calls to
the same conference ID get routed to the same MCU.