User`s manual
H.323 User's Manual 5. Web Management
Version 5.0 99 December 2006
Alternative Routing – (When Gatekeeper isn’t used) an alternative IP destination for
telephone number prefixes is available. To associate an alternative IP address to
called telephone number prefix, assign it with an additional entry (with a different IP
address), or use an FQDN that resolves to two IP addresses. Call is sent to the
alternative destination when one of the following occurs:
• No ping to the initial destination is available, or when poor QoS (delay or packet
loss, calculated according to previous calls) is detected, or when a DNS host
name is not resolved. For detailed information on Alternative Routing, refer to
Section 8.8 on page 267.
• When a release reason that is defined in the ‘Reasons for Alternative Tel to IP
Routing’ table is received. For detailed information on the ‘Reasons for
Alternative Routing Tables’, refer to Section 5.5.4.5 on page 104.
Note: If the alternative routing destination is the gateway itself, the call can be
configured to be routed back to PSTN. This feature is referred to as ‘PSTN
Fallback’, meaning that if sufficient voice quality is not available over the IP
network, the call is routed through legacy telephony system (PSTN).
Tip: Tel to IP routing can be performed either before or after applying the
number manipulation rules. To control when number manipulation is
performed, set the Tel to IP Routing Mode (or RouteModeTel2IP ini file)
parameter (described in Table 5-14).
You can also configure the Tel to IP Routing table using the ini file parameter Prefix (refer
to Section 6.5.9 on page 236).
¾ To configure the Tel to IP Routing table, take these 6 steps:
1. Open the ‘Tel to IP Routing’ screen (Protocol Management menu > Routing Tables
submenu > Tel to IP Routing option); the ‘Tel to IP Routing’ screen is displayed
(shown in Figure 5-16).
Figure 5-16: Tel to IP Routing Table Screen
2. In the ‘Tel to IP Routing Mode’ field, select the Tel to IP routing mode (refer to Table
5-14).
3. From the ‘Routing Index’ drop-down list, select the range of entries that you want to
edit.
4. Configure the Tel to IP Routing table according to Table 5-14.
5. Click the Submit button to save your changes.
6. To save the changes so they are available after a power fail, refer to Section 5.9.2 on
page 193.