Server Redundancy - Yealink SIP-T4X Administration Manual

Administrator's Guide for SIP-T4X IP Phones
Procedure
Server redundancy can be configured using the configuration files or locally.
Configuration File
Local
If a domain name is configured for a SIP server, the IP address(es) associated with that
domain name will be discovered through DNS as specified by RFC 3263. The DNS query
involves NAPTR, SRV and A queries, which allows the IP phone to adapt to various
deployment environments. The IP phone performs the NAPTR query for the SRV pointer
and service type (UDP , TCP and TLS), the SRV query on the record returned from the
NAPTR for the host name and the port number, and the A query for the IP addresses.
If a port is set to 0 and the transport type is set to DNS-NAPTR, NAPTR and SRV queries
will be tried before falling back to A query. If no port is found through the DNS query,
5060 will be used. If an explicit port (except 0) is specified and the transport type is set
to DNS-NAPTR, the only lookup will be an A query.
The following details the procedures of DNS query for the IP phone to resolve the
domain name of working server into the IP address, port and transport protocol.
NAPTR (Naming Authority Pointer)
First, the IP phone sends the NAPTR query to get the SRV pointer and service type. The IP
phone performs a NAPTR query for the domain name. Example of NAPTR records:
order
IN NAPTR 90
IN NAPTR 100
164
<MAC>.cfg
Web User Interface
pref flags service
50 "s" "SIP+D2T"
50 "s" "SIP+D2U"
Configure the server
redundancy on the IP phone.
For more information, refer to

Server Redundancy

338.
Configure the server
redundancy on the IP phone.
Navigate to:
http://<phoneIPAddress>/servl
et?p=account-register&q=load
&acc=0
regexp replacement
"" _sip._tcp.example.com
"" _sip._udp.example.com
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