User`s manual

Mediant 2000 & TP-1610 & TP-260
SIP User's Manual 76 Document #: LTRT-68805
5.5.5.5 Reasons for Alternative Routing
The Reasons for Alternative Routing screen includes two tables (TelÆIP and IPÆTel).
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 IPÆTel calls is provided in Q.931 notation. The release reason for
TelÆIP calls is provided in SIP 4xx, 5xx and 6xx response codes. For TelÆIP calls an
alternative IP address, for IPÆTel calls an alternative trunk group.
Refer to ‘Tel to IP Routing Table’ on page 70 for information on defining an alternative IP
address. Refer to the ‘IP to Trunk Group Routing Table’ on page 72 for information on
defining an alternative trunk group.
You can use this table for example:
For TelÆIP 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 IPÆTel 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
6-7.
Note: The reasons for alternative routing option for TelÆIP calls only apply when Proxy
isn’t used.
¾ 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 5-12: 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 5.9.2 on
page 124.