Nortel Networks TP-1610 SIP Reasons for Alternative Routing, You can use this table for example

Mediant 2000 SIP

5.8.4.4Reasons for Alternative Routing

The Reasons for Alternative Routing screen includes two tables (Tel IP and IP Tel). Each table enables you to define up to 4 different release reasons. If a call is released as a result of one of these reasons, the gateway tries to find an alternative route to that call. The release reason for IP Tel calls is provided in Q.931 notation. The release reason for Tel IP calls is provided in SIP 4xx, 5xx and 6xx response codes. For Tel IP calls an alternative IP address, for IP Tel calls an alternative trunk group.

Refer to ‘Tel to IP Routing Table’ on page 49 for information on defining an alternative IP address. Refer to the ‘IP to Trunk Group Routing Table’ on page 51 for information on defining an alternative trunk group.

You can use this table for example:

For Tel	IP calls, when there is no response to an Invite message (after Invite retransmissions),
and the gateway then issues an internal 408 ‘No Response’ implicit release reason.
For IP	Tel calls, when the destination is busy, and release reason #17 is issued or for other call

releases that issue the default release reason (#3). Refer to ‘DefaultReleaseCause’ in Table 6-3.

Note: The reasons for alternative routing option for Tel IP calls only applies when Proxy isn’t used.

To configure the reasons for alternative routing, take these 5 steps:

1.Open the ‘Reasons for Alternative Routing’ screen (Protocol Management menu > Routing Tables submenu > Reasons for Alternative Routing option); the ‘Reasons for Alternative Routing’ screen is displayed.

Figure 5-8: Reasons for Alternative Routing Screen

2.In the ‘IP to Tel Reasons’ table, from the drop-down list select up to 4 different call failure reasons that invoke an alternative IP to Tel routing.

3.In the ‘Tel to IP Reasons’ table, from the drop-down list select up to 4 different call failure reasons that invoke an alternative Tel to IP routing.

4.Click the Submit button to save your changes.

5.To save the changes so they are available after a power fail, refer to Section 5.12 on page 84.

Mediant 2000 SIP User’s Manual 54 Document #: LTRT-72504