Parameter name
Default value
Recommended settings
REGISTERWAIT
900
This parameter represents
number of seconds between
register refreshes. It is
recommended to set the value to
“120” to “180” seconds.
This enables faster recovery
detection of signaling servers.
Related links
Redundancy in a Netsapiens environment
DNS resolution
In the Open SIP modes, phone uses DNS service to lookup a Fully Qualified Domain Name
(FQDN) in the host part of SIP_CONTROLLERS_LIST parameter. It uses combination of NAPTR,
SRV and a DNS record to resolve a FQDN into prioritized list of
[IP address, protocol,
port]
set. Administrators must ensure that DNS is configured to return fixed order of servers for
the FQDN.
Types of DNS records
The phones use the user domain information and DNS lookups on various DNS records to identify
the list of servers and their priority. The phones use a combination of the following DNS records to
resolve a user domain into a prioritized list of sets in the format
[IP address, protocol,
port]
.
• Name Authority Pointer (NAPTR) record: Used to identify the preferred protocol to be used
for a specific service. The protocol can be UDP, TCP, or TLS. It provides the information
required for the subsequent DNS SRV record lookup.
• SRV record: Used to identify the list of hosts as FQDNs that provide a service using a
specific protocol in a domain. It also provides port information the service is provided at along
with the priority of the hosts. SRV lookup provides the list of hosts as FQDNs and the ports
used by each host for a service using a protocol.
• A record: Provides a mapping of a host name as a FQDN to an IPV4 address. It also
provides the value of time to live (TTL). TTL indicates the duration for which the value can be
cached and used by a DNS client.
SIP server redundancy configuration
April 2020
Installing and Administering Avaya J100 series IP Phones in an Open SIP
environment
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