Yealink T5 Series, Administrator'S Manual

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Administrator’s Guide for SIP-T58V/T58A/T56A/CP960 IP Phones
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The phone moves to the next available server after three failed attempts.
Permitted
Values
Integer from 0 to 20
Default 3
Web UI Account->Register->SIP Server Y->Server Retry Counts
Parameter
account.X.sip_server.Y.failback_mode
[1][2]
<MAC>.cfg
Description
It configures the mode for the phone to retry the primary server in failover.
Note : It works only if “account.X.sip_server.Y.address” is set to the domain name of the SIP server.
Permitted
Values
0 -newRequests: all requests are sent to the primary server first, regardless of the last server that was used.
1 -DNSTTL: the phone will send requests to the last registered server first. If the time defined by DNSTTL
on the registered server expires, the phone will retry to send requests to the primary server.
2 -Registration: the phone will send requests to the last registered server first. If the registration expires,
the phone will retry to send requests to the primary server.
3 -duration: the phone will send requests to the last registered server first. If the time defined by the
“account.X.sip_server.Y.failback_timeout” parameter expires, the phone will retry to send requests to the
primary server.
Default 0
Parameter
account.X.sip_server.Y.failback_timeout
[1][2]
<MAC>.cfg
Description
It configures the timeout (in seconds) for the phone to retry to send requests to the primary server after
failing over to the current working server.
If you set the parameter to 0, the phone will not send requests to the primary server until a failover event
occurs with the current working server.
If you set the parameter between 1 and 59, the timeout will be 60 seconds.
Note : It works only if “account.X.sip_server.Y.failback_mode” is set to 3 (duration).
Permitted
Values
0, Integer from 60 to 65535
Default 3600
[1]
X is the account ID. For T58V/T58A/T56A, X=1-16; for CP960, X=1.
[2]
Y is the server ID. Y=1-2.
SIP Server Name Resolution
If a domain name is configured for a server, the IP address(es) associated with that domain name will be resolved
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 NAPTR query for the NAPTR pointer and trans-
port protocol (UDP, TCP and TLS), the SRV query on the record returned from the NAPTR for the target domain name
and the port number, and the A query for the IP addresses.
If an explicit port (except 0) is specified, A query will be performed only. If a server port is set to 0 and the transport
type is set to DNS-NAPTR, NAPTR and SRV queries will be tried before falling to A query. If no port is found through
the DNS query, 5060 will be used.