Technical data

Features

EN4442EN00EN_0001

Siemens

For more details please refor to Chapter 14, “Standby Board HG 3500”.

4.15.2.3 Secondary Gateways

In order to protect against higher level failures (e.g. Access Point, host failures) secondary

gateways can be added to the system. A secondary gateway is an additional, fully configured

gateway for an IP client located anywhere within a HiPath 4000 system. Note that each IP user

that is backed up via a secondary gateway will have 2 extensions, e.g. x1333 on the primary

gateway and extension x5333 on the secondary gateway.

In case communication to the primary gateway is lost (e.g. due to a shelf or host failure), the IP

phone will attempt to register with the secondary gateway. As long as the secondary gateway

is operational and IP connectivity is available, all phones backed up with secondary gateways

will register with their secondary gateway and will be fully operational.

While registered with the secondary gateway the users will have all features available that have

been enabled on the secondary extension. Incoming calls terminating on the primary extension

will be automatically forwarded to the secondary extension using a new feature called

“Alternate Routing on Error”.

Figure 4-2 HG 3500 Secondary Gateway Operation

In order to minimize the number of secondary gateways and additional trunks required for

operating in failure mode, the following measures can be taken:

● Secondary gateways can be configured with a higher blocking rate, which will limit the

number of IP users that can make concurrent calls.

● Minimize the additional trunk required for secondary gateways via “undertrunking”.

Note that these measures are entirely optional and up to the customer’s preference. However,

it may be a reasonable approach to limit resources (and thus cost) for operation in failure mode

because this is a scenario that is very unlikely to become reality.