In this redundancy option, several (N) Media servers provide local support for branches, and a central Media server serves as backup for all other servers.
In case of the N+1 redundancy, N represents the number of primary Media servers. These are the Media servers that are in top position in the list of Media servers at a destination with Media servers. If N is greater than 1, an origin destination must be created for setting up a specific Media server for a specific branch. This number corresponds to the number of branches and headquarters that have a local Media server.
The following two figures show the N+1 redundancy for Media servers:
If the Telephony Control Server cluster nodes share the same branch
If the Telephony Control Server cluster nodes are geographically separated
In both figures, three active and one backup Media server are available for a 3+1 redundancy.
Figure 1. N+1 redundancy – Telephony Control Server cluster nodes at the same branch
Figure 2. N+1 redundancy – Telephony Control Server cluster nodes geographically separated
In case of a failure and depending on the failure type, the following happens:
If an Telephony Control Server node fails, the partner node adopts its function. The MGCP signaling manager on the partner node still uses the Media servers like it did before the failure.
Media Server Failure
If the Media server in a branch fails, Telephony Control Server registers this event and the branch uses the central backup Media server from then on. Existing connections to the failed Media server are not switched over and drop away. The other branches carry on using their own Media servers.
Failure of a Branch
If a branch fails completely, the other branches carry on using their own Media servers and are not affected by the failure.
If the WAN connection to a specific branch collapses, the branch concerned cannot receive tones and system announcements. The subscribers isolated in the branch can still use the Media server inasmuch as they are registered with an Telephony Control Server edge system anew.
The other branches are not affected by the failure.
Support of Several Languages
The backup Media server must be configured for all languages required by the different Media servers of the branches.
Parent topic: Media Server Redundancy on Telephony Control Server