User's Manual

• SERVER_IP[x]_1
• SERVER_IP[x]_2
where x = the domain number from 1 to 5.
If the IP Deskphone attempts to log on using these configured addresses and fails to do so,
the IP Deskphone then tries to discover the IP addresses using DNS. If there is no primary or
secondary SIP domain IP address configured, then the IP Deskphone uses DNS to determine
the IP address. If only SERVER_IP[x]_2 is configured (SERVER_IP[x]_1 is 0.0.0.0), then DNS
Lookup is used first; if DNS Lookup fails, only then is the secondary IP address tried.
The DNS Lookup feature tries to obtain SIP domain IP addresses through DNS SRV records,
using the domain name as a parameter for UDP, TCP, and TLS. Multiple SRV records can be
configured for each domain and for each transport protocol (UDP, TCP and TLS). The
hostname is returned instead of the IP address. The hostname must point to an address record
(A or AAAA record).
SRV record example:
_sip._tcp.example.com. 86400 IN SRV 0 5 5060 sipserver.example.com
where:
• sip = the desired service
• tcp = the transport protocol
• example.com = the configured domain name
• 5060 = the port to be used
• sipserver.example.com = the SIP proxy to be used (hostname is replaced by the IP
address using A/AAAA records)
The DNS Lookup feature then tries to find the IP address of the SIP domain in A/AAAA records
on the DNS Server. Only the IP address is returned; therefore, default ports are used — 5060
for UDP/TCP and 5061 for TLS.
Important:
If the Fail Back to Primary feature is enabled, then DNS lookup is not used. In this case, you
must configure both primary and secondary IP addresses for a domain.
Caution:
If DNS servers are not properly configured or do not respond, DNS Lookup can take a long
time until all necessary requests are sent and corresponding timers expire.
Server Profiles
A System Configuration file allows the administrator to specify a list of domains to which the
IP Deskphone can connect. The administrator can specify up to five different SIP domains.
Features
214 SIP Software for Avaya 1100 Series IP Deskphones-Administration November 2012
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