Server Redundancy - Matrix Sparsh VP110 User Manual

Server Redundancy

Server redundancy is often required in VoIP deployments to ensure continuity of phone service, for events where
the server needs to be taken offline for maintenance, the server fails, or the connection between the IP phone and
the server fails.
Two types of redundancy are possible. In some cases, a combination of the two may be deployed:
• Failover: In this mode, the full phone system functionality is preserved by having a second equivalent
capability call server take over from the one that has gone down/off-line. This mode of operation should be
done using the DNS mechanism from the primary to the secondary server.
• Fallback: In this mode, a second less featured call server with SIP capability takes over call control to
provide basic calling capability, but without some advanced features offered by the working server (for
example, MWI). IP phones support configuration of two SIP servers per SIP registration for fallback
purpose.
Phone Configuration for Redundancy Implementation
To assist in explaining the redundancy behavior, an illustrative example of how an IP phone may be configured is
shown as below. In the example, server redundancy for fallback and failover purposes is deployed. Two separate
SIP servers (a working server and a fallback server) are configured for account (line) registration.
• Working Server: Server 1 is configured with the domain name of the working server. For example,
'matrix_ippbx.com'. DNS mechanism is used such that the working server is resolved to multiple SIP
servers for failover purpose. The working server is deployed in redundant pairs, designated as primary and
secondary servers. The primary server has the highest priority server in a cluster of servers resolved by
256
Working Server: matrix_ippbx.com
Fallback Server: 192.168.1.15
Matrix SPARSH VP110 User Guide