Sas Operating Modes - AudioCodes Mediant 600 User Manual

SIP User's Manual
8.4.1

SAS Operating Modes

The device's SAS application can be implemented in one of the following main modes:

Outbound Proxy: In this mode, SAS receives SIP REGISTER requests from the
enterprise's UAs and forwards these requests to the external proxy (i.e., outbound
proxy). When a connection with the external proxy fails, SAS enters SAS emergency
state and serves as a proxy, by handling internal call routing for the enterprise's UAs -
routing calls between UAs and if setup, routing calls between UAs and the PSTN. For
a detailed description, see ''SAS Outbound Mode'' on page 358.

Redundant Proxy: In this mode, the enterprise's UAs register with the external proxy
and establish calls directly through the external proxy, without traversing SAS (or the
device per se'). Only when connection with the proxy fails, do the UAs register with
SAS, serving now as the UAs redundant proxy. SAS then handles the calls between
UAs, and between the UAs and the PSTN (if setup). This mode is operational only
during SAS in emergency state. This mode can be implemented, for example, for
proxies that accept only SIP messages that are sent directly from the UAs. For a
detailed description, see ''SAS Redundant Mode'' on page 360.
Note:
Version 6.2
It is recommended to implement the SAS outbound mode.
357
8. IP Telephony Capabilities
February 2011