Nortel Networks Remote Gateway 50 - Manual (Page 16)

Page 16 of 258 Overview
553-3001-207 Standard 2.00 January 2006
The SRG is implemented on a BCM50 platform and is connected to a
CS 1000 at the main office over a LAN or a WAN. This configuration allows
the call processing for the IP Phones at the SRG site to be centralized at the
main office. The Call Server at the main office provides the call processing
for the IP Phones in both the main office and branch offices. The SRG
provides call processing functionality to telephones in local mode and local
analog devices. The SRG also provides digital and analog trunk access to the
local Public Switched Telephone Network (PSTN).
In order for devices in the CS 1000 network to access analog devices at the
SRG or to access the PSTN at the SRG, virtual trunks are used over the LAN/
WAN.
If the main office fails to function, or if there is a network outage, the SRG
provides service to the telephones located at the branch office. This enables
the IP Phones to survive the outage between the branch office and the main
office.
The SRG is designed to work with a main office only if the main office and
the SRG use a common dialing plan. Any other configuration is not
guaranteed to work reliably. Since the Call Server and the SRG handle dialing
slightly differently, ensure that any settings you use for the main office, that
need to interact with the SRG, can be accommodated by the SRG call
processing.
Figure 1 on page 17 shows the networking among the main office, SRG, and
IP Phones.