Phone Registration - Yealink SIP-T2XP Administrator's Manual

Administrator's Guide for SIP-T2xP IP Phones
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 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 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 lesser functionality than the working
server.

Phone Registration

Registration methods of the fallback mode include:
Concurrent registration: The IP phone registers to two SIP servers (working 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 of the richer features
offered by the working server (default registration method).
Successive registration: The IP phone only registers to one server at a time. The IP

phone first registers to the working server. In a failure situation, the IP phone
registers to the fallback server.
When registering to the working server, the IP phone must always register to the primary
server first except in failover conditions. When the primary server registration is
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