AudioCodes 420HD - Device Registration Failover;Failback; Failover; Table 17-4: Device Registration Failover Parameters

400HD Series IP Phones
Administrator's Manual 100 Document #: LTRT-11950
17.2.2 Device Registration Failover/Failback
17.2.2.1 Failover
This feature enables a secondary server to take over the functions of the primary server on
the enterprise network, if SIP communication between the SIP access device and the
primary proxy server is blocked or delayed or the primary server isn't available.
No phone functionality is lost when the secondary server takes over.
Note:
• For failover to function, the Proxy DNS server must be configured with a list of the
names of the proxies, in order and priority, i.e, SRV record. Before the phone tries to
register, it performs an NAPTR / SRV query (see the table below for an explanation of
these). The DNS server send a prioritized list. The phone sends a Registration
request to the first SIP server; if it isn’t responsive in n time retries (i.e.,
'outgoing_request_no_response_timeout' parameter), it goes to the second, etc.,
until it gets a response.
• SIP Proxy/Outbound Proxy must be configured as the host name.
 To configure failover using the Configuration File:
• Use the table below as reference.
Table 17-4: Device Registration Failover Parameters
Parameter Description
SIP Transport Protocol
[voip/signalling/sip/transport_protocol]
Either:
 UDP (default)
 TCP
 TLS encryption
In the SIP protocol, Name Authority
Pointers (NAPTRs) are used to map
servers and user addresses. Combined
with Service Records (SRVs), they
enable determining the service types
available for a name, the name to use for
an SRV lookup, and the port and 'A'
DNS records to use to find the IP for the
service.
[voip/signalling/sip/outgoing_request_no_response_timeout_ms]
This is the timeout, in milliseconds, that
lapses until the phone failovers to the
secondary proxy. Default: 32000
Outbound Proxy IP Address or Host Name
Configure this parameter as an SRV
host name.
Outbound Proxy Port
[voip/signalling/sip/sip_outbound_proxy/port]
Configure a value of 65535 for this
parameter.
Configure the parameter
when you're using an Outbound Proxy.
Either configure this parameter or the
parameter 'Proxy Port'.