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Administrator’s Guide for VP530 IP
Video
Phone
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deployment environments. The DNS SRV query is configurable on a per-account basis.
NAPTR (Naming Authority Pointer)
First, the IP phone sends the NAPTR query to get the SRV pointer and service type. As an
example, consider the IP phone wishes to resolve “sip:[email protected]”. The IP
phone performs a NAPTR query for the domain name. The sample of the NAPTR records
for reference:
order pref flags service regexp replacement
IN NAPTR 90 50 "s" "SIP+D2T" "" _sip._tcp.example.com
IN NAPTR 100 50 "s" "SIP+D2U" "" _sip._udp.example.com
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 to process multiple NAPTR records with
the same order value. Lower value is MORE preferred.
flags
The flag “s” means to do an SRV lookup.
service
Specify the service available for SIP by the following rules:
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 DNS name to be used 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 use "sip:[email protected]" for the next NAPTR
query.
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. The sample of the SRV records for reference:
Priority Weight Port Target
IN SRV 0 1 5060 server1.example.com
IN SRV 0 2 5060 server2.example.com
Summary of Contents for VP530 IP
Page 1: ......
Page 4: ......
Page 12: ......
Page 111: ...Configuring Basic Features 99...
Page 153: ...Configuring Advanced Features 141...
Page 171: ...Configuring Security Features 159...
Page 182: ...Administrator s Guide for VP530 IP Video Phone 170 Phonebook on page 266...
Page 183: ...Resource Files 171...
Page 194: ...Administrator s Guide for VP530 IP Video Phone 182 3 Click OK to confirm the resetting...
Page 195: ...Troubleshooting 183...
Page 344: ...Administrator s Guide for VP530 IP Video Phone 332...