Mediant 2000 SIPMediant 2000 SIP User’s Manual 54 Document #: LTRT-725045.8.4.4 Reasons for Alternative RoutingThe Reasons for Alternative Routing screen includes two tables (TelÆIP and IPÆTel). Each tableenables you to define up to 4 different release reasons. If a call is released as a result of one ofthese reasons, the gateway tries to find an alternative route to that call. The release reason forIPÆTel calls is provided in Q.931 notation. The release reason for TelÆIP calls is provided in SIP4xx, 5xx and 6xx response codes. For TelÆIP calls an alternative IP address, for IPÆTel calls analternative trunk group.Refer to ‘Tel to IP Routing Table’ on page 49 for information on defining an alternative IPaddress. Refer to the ‘IP to Trunk Group Routing Table’ on page 51 for information on defining analternative 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 callreleases that issue the default release reason (#3). Refer to ‘DefaultReleaseCause’ in Table 6-3.Note: The reasons for alternative routing option for TelÆIP calls only applies when Proxy isn’tused.¾ To configure the reasons for alternative routing, take these 5 steps:1. Open the ‘Reasons for Alternative Routing’ screen (Protocol Management menu > RoutingTables submenu > Reasons for Alternative Routing option); the ‘Reasons for AlternativeRouting’ screen is displayed.Figure 5-8: Reasons for Alternative Routing Screen2. In the ‘IP to Tel Reasons’ table, from the drop-down list select up to 4 different call failurereasons 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 failurereasons 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 page84.
