Chapter 3 CS 1000 considerations
37
Survivable Remote Gateway 50 Configuration Guide
Recovery to normal mode
If an IP Phone is in Local Mode due to WAN failure, or main office component failure, the SRG
tries to communicate with the main office TPS at regular intervals. Once communication is
established with the main office call server, the idle SRG IP Phones are automatically redirected
and reregistered to the main office. IP Phones that were busy at the time communication was
reestablished complete the call in Local Mode, and then reregister with the main office once the
call is complete.
Local mode operation
When an SRG IP Phone is in Local Mode, the user has full access to the services configured at the
SRG (analog devices or analog or digital trunks) and to other IP Phones registered to the SRG. In
Local Mode, the IP Phones can make local calls to other IP Phones and other analog (500/
2500-type) telephones at the branch office. They can also be used to make outgoing PSTN calls
and receive incoming calls as usual. SRG IP Phones can access the main office IP Phones or other
branches by routing through the local PSTN.
Virtual trunk capacity
The SRG50’s capacity to support a number of simultaneous calls depends on the specific codec
type used.
In normal mode, the codec selection used is controlled by specific programming of the CS1000. In
this case: SRG50 supports up to a maximum of 15 Virtual trunks unless both the intrazone and
interzone codecs are configured as Best Quality (G.711) in which case, the maximum number of
virtual trunks would be 24.
In local mode, if the WAN has failed, there are no longer any virtual trunks available between the
SRG50 and CS1000. However, the SRG50 will continue to convert calls from IP terminals for
communication via the PSTN. In this case, if G.711 is used (recommended), the number of
simultaneous calls from IP terminals to the PSTN supportable is a maximum of 24.
Vacant Number Routing
The SRG50 does not support Vacant Number Routing (VNR). Instead, the SRG50 uses Call
Forward All Calls to emulate VNR for the IP telephones that are in normal mode. Call Forward All
Calls is automatically cancelled when the phones revert to local mode.
IMPORTANT!
When a telephone or trunk in the main office calls a branch office
IP telephone that has switched to local mode due to WAN failure, the
call is treated according to the main office call redirection configuration
(such as forwarding to voicemail or continuous ringback).
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...
