Yealink SIP-T4X, Administrator'S Manual

Page: 185 / 475

Configuring Advanced Features
169
Parameters are explained in the following table:
Parameter Description
order
Specify preferential treatment for the specific record. The order
is from lowest to highest, lower order is MORE preferred.
pref
Specify the preference for processing multiple NAPTR records
with the same order value. Lower value is MORE preferred.
flags
The flag ―s‖ means to perform an SRV lookup.
service
Specify the transport protocols supported by the domain server:
SIP+D2U: SIP over UDP
SIP+D2T: SIP over TCP
SIP+D2S: SIP over SCTP
SIPS+D2T: SIPS over TCP
regexp Always empty for SIP services.
replacement Specify a domain name for the next query.
The IP phone picks the first record, because its order of 90 is lower than 100. The pref
parameter is unimportant as there is no other record with order 90. The flag ―s‖
indicates performing the SRV query next. TCP will be used, targeted to a host
determined by an SRV query of ―_sip._tcp.example.com‖. If the flag of the NAPTR record
returned is empty, the IP phone will perform the NAPTR query again according to the
previous NAPTR query result.
SRV (Service Location Record)
The IP phone performs a SRV query on the record returned from the NAPTR for the host
name and the port number. Example of SRV records:
Priority Weight Port Target
IN SRV 0 1 5060 server1.example.com
IN SRV 0 2 5060 server2.example.com
Parameters are explained in the following table:
Parameter Description
Priority
Specify preferential treatment for the specific host entry. Lower
priority is MORE preferred.
Weight
When priorities are equal, weight is used to differentiate the
preference. The preference is from highest to lowest. Keep the
same to load balance.
Port Identify the port number to be used.
Target Identify the actual host for an A query.