Phoenix Audio Spider MT505 SIP Administraor Guide - Manual (Page 12)

Redundant Proxy Address The IP address or host name of the redundant proxy.
The default value is 0.0.0.0.
Note: This parameter is applicable only if the parameter
use_redundant_proxy is set to 1.
Redundant Proxy Port The UDP or TCP port of the redundant proxy server.
The valid range is 1024 to 65535. The default value is 5060.
Note: This parameter is applicable only if the parameter
use_redundant_proxy is set to 1.
Redundant Proxy Keep Alive Period Defines the interval in seconds for sending keep-alive
messages to the proxy.
The valid range is 0 to 300. The default value is 60.
Note: This parameter is applicable only if the parameter
use_redundant_proxy is set to 1.
Switch back to Primary SIP proxy when
available Determines the proxy redundancy mode.
 Asymmetric mode. (default)
 Symmetric mode.
The Redundant Proxy feature allows the configuration of a
backup SIP proxy server to increase QoS stability. Once this
feature is enabled, the phone identifies cases where the
primary proxy does not respond to SIP signaling messages.
In these scenarios, the phone registers to the redundant
proxy and the phone seamlessly continues normal
functionality, without the user noticing any connectivity failure
or malfunction with the primary proxy.
The Redundant Proxy feature includes two operational
modes:
 Asymmetric mode: the primary proxy is assigned a
higher priority for registration than the redundant proxy.
In the Asymmetric mode, once the phone is registered to
the primary proxy, it sends keep-alive messages (using
SIP OPTIONS messages) to the primary proxy. If the
primary proxy does not respond, the phone registers to
the redundant proxy, but continues sending keep-alive
messages to the primary proxy. If the primary proxy
responds to these keep-alive messages, the phone re-
registers to the primary proxy. Therefore, the phone
assigns the primary proxy a higher priority for
registration.
 Symmetric mode: both proxies are assigned the same
priority for registration. In the Symmetric mode, once the
phone is registered to a proxy, it sends keep-alive
messages to this proxy. The phone switches proxies only
once the proxy to which it has registered does not
respond. Therefore, the phone assigns both proxies the
same priority for registration
In both modes, the following applies:
If the phone is not registered (i.e., if the proxy server
–
redundant or primary –to which the phone currently tries to
register does not respond), the phone attempts to register to
an alternative proxy. These attempts continue until the phone