Technical data

Features
EN4442EN00EN_0001
© 2007 Siemens AG
Siemens
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1. Adding one or multiple standby gateways to the system protects against individual
gateway failures
2. Providing full redundancy for IP clients via secondary gateways will protect against higher
level failures, like entire Access Point or host failures.
4.15.2.2 Standby Gateways
One or multiple standby HG 3500 IP line gateways can be defined in the system that will take
over in case any of the installed line gateways fails.
This concept is very efficient and cost effective because a single gateway can protect multiple
gateways against failure. However, a single gateway cannot protect against multiple gateways
failing simultaneously, which is highly unlikely.
In case of a failure, the system will reprogram a standby gateway with the parameters of the
failed gateway which will enable the IP clients to re-login and resume standard operation.
IP phones will automatically register with the activated standby gateway and no administrative
action is required. Note that users keep the same features and extensions while operating off
the standby gateway.
Figure 4-1 HG 3500 Standby Gateway Operation
Standby gateways can be located in the host system and/or on an IP Access point. The only
requirement is that all active and standby line gateways have to reside in the same local IP
subnet.
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Important
Standby gateways and IP clients have to reside within the same system!
E.g.: a standby gateway located in one system cannot control IP clients controlled
normally by a gateway located in another system.
Standby gateways at IP Access Points will not protect IP users at the host against a
host failure because failures at higher levels (e.g. shelf, AP, host or power failures)
will not automatically trigger a switchover.