Chapter 1 Getting started
17
Survivable Remote Gateway 50 Configuration Guide
SRG50 operating modes
The SRG50 has two operating modes: normal and local.
Normal mode
In normal mode
(Figure 1)
, the SRG50 is connected to the main office call server over a WAN
using VoIP trunks. From the perspective of the main office, the SRG50 is a branch office.
Figure 1
Normal mode
IP telephones connected at the SRG50 are registered with the main office call server and are under
main office control. They operate as branch user sets and have access to all telephony services and
features that the call server offers to IP telephones connected directly to the main office.
When a branch user set initiates a local PSTN call, the main office sets up the call using the VoIP
trunks, which establishes a local media path. Emergency Services Access calls are similarly routed
to the SRG50 PSTN. For main office callers, the SRG50 acts as a VoIP-PSTN gateway during
normal mode.
When call forwarding has been configured, incoming PSTN calls to the branch user set are
forwarded over VoIP trunks to the main office, which terminates the call at the branch user.
Similarly, calls from analog telephones connected to the SRG50 to the branch user set are
forwarded to the main office over VoIP trunks, which then terminates the call at the branch user.
Calls from the branch user set to the analog telephones at the SRG50 are routed over the VoIP
trunks to terminate at the analog telephone. In all these call scenarios, only signaling messages go
through the VoIP trunk. The media path is set up directly between the branch user set and the voice
gateway at the SRG50. This means that these calls do not use any WAN bandwidth between the
main office and the branch office after calls are established.
Branch office
Main office
VoIP connection over WAN
IP phones
SRG50
IP phones
Normal mode
Software
phones
WLAN
handsets
Summary of Contents for SRG50
Page 1: ...Part No N0060720 03 December 2007 Survivable Remote Gateway 50 Configuration Guide...
Page 4: ...4 Task List N0060720 N0060720 Glossary 107 Index 109...
Page 8: ...8 Contents N0060720...
Page 26: ...26 Chapter 1 Getting started N0060720 N0060720...
Page 50: ...50 Chapter 3 CS 1000 considerations N0060720 N0060720 Figure 6 S1000 IP Terminal Details panel...
Page 62: ...62 Chapter 4 CS 2000 considerations N0060720 N0060720...
Page 100: ...100 Chapter 8 Troubleshooting N0060720...
Page 106: ...106 Telephone features in normal and local mode N0060720...