Call Bridges operate as a single entity when clustered, scaling available resources. A prerequisite is to have a fully configured and functioning Database cluster. (Read PART 5 of this blog series).

Two cluster types exist. Peer to peer and via Call Control. Most efficient method is Peer-to-Peer. Where Call bridges route media directly between themselves and not via a call control server (CUCM).

Steps to Configure a Call Bridge Cluster

1. Log into Web Admin of each Call Bridge CMS Server. Navigate to Configuration -> Cluster. Enter a unique name for the Call Bridge. Eg CMS_01 (must not contain spaces).
2. On the first Call Bridge, go to Configuration -> Cluster and add All Cluster nodes into table using the above Unique Node Names. Do not enter the “Peer Link SIP Domain” field. Also ensure the Address is https://fqdn:445 (webAdmin Port). Ensure this address is DNS resolvable!

Another key factor to this configuration is the dial plan. For inter-peer calls.. (between Call Bridges in a Call bridge Cluster), a route must exist for the IP Address for peer members. There is a required when the “Peer Link SIP Domain” is left blank for the Call bridge Cluster.

*If you do not configure these outbound rules, you will see an error “remote media link to call bridge CALLBRIDGE failed for call”.

The impact will see a single video conference that is split between two CMS Call bridges.. Thus the conference participants will only see other participants on that same Call Bridge Host.