Phone Registration - Yealink SIP-T48G Administrator's Manual

fallback and failover purposes is deployed. Two separate servers (a working server
and a fallback server) are configured for per line registration.
Working Server: Server 1 is configured with the domain name of the working server.
For example: yealink.pbx.com. DNS mechanism is used such that the working
server is resolved to multiple 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 the
DNS server. The secondary server backs up a primary server when the primary
server fails and offers the same functionality as the primary server.
Fallback Server: Server 2 is configured with the IP address of the fallback server. For
example, 192.168.1.15. A fallback server offers less functionality than the working
server.

Phone Registration

Registration method of the failover mode:
The IP phone must always register to the primary server first except in failover
conditions. If this is unsuccessful, the phone will re-register as many times as configured
until the registration is successful. When the primary server registration is unavailable,
the secondary server will serve as the working server.
Registration methods of the fallback mode include:
Concurrent registration (default): The IP phone registers to two SIP servers (working
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server and fallback server) at the same time. In a failure situation, a fallback server
can take over the basic calling capability, but without some advanced features (for
example, shared lines, call recording and MWI) offered by the working server. It is
not applicable to outbound proxy servers
Successive registration: The IP phone only registers to one server at a time. The IP
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Configuring Advanced Features
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