Matrix Sparsh VP110 User Manual page 270

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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.matrix_ippbx.com". If the flag of the NAPTR record
returned is empty, the IP phone will perform NAPTR query again according to the previous NAPTR query result.
SRV (Service Location Record)
The IP phone performs an SRV query on the record returned from the NAPTR for the host name and the port
number. Example of SRV records:
Priority Weight Port
IN SRV 0 1
IN SRV 0 2
Parameters are explained in the following table:
Parameter
Priority
Weight
Port
Target
SRV query returns two records. The two SRV records point to different hosts and have the same priority 0. The
weight of the second record is higher than the first one, so the second record will be picked first. The two records
also contain a port "5060", the IP phone uses this port. If the Target is not a numeric IP address, the IP phone
performs an A query. So in this case, the IP phone uses "server1.matrix_ippbx.com" and
"server2.matrix_ippbx.com" for the A query.
A (Host IP Address)
The IP phone performs an A query for the IP address of each target host name. Example of A records:
Server1.matrix_ippbx.com IN A 192.168.1.13
Server2.matrix_ippbx.com IN A 192.168.1.14
The IP phone picks the IP address "192.168.1.14" first.
Outgoing Call When the Working Server Connection Fails
When a user initiates a call, the phone will go through the following steps to connect the call:
• Sends the INVITE request to the primary server.
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Specify a domain name for the next query.
Target
5060 server1.matrix_ippbx.com
5060 server2.matrix_ippbx.com
Specify preferential treatment for the specific host entry. Lower priority is
more preferred.
When priorities are equal, weight is used to differentiate the preference.
The preference is from highest to lowest. Keep the same to load balance.
Identify the port number to be used.
Identify the actual host for an A query.
Description
Matrix SPARSH VP110 User Guide