AudioCodes Mediant 500 E-SBC, Руководство пользователя

Страница: 404 / 920

User's Manual 404 Document #: LTRT-10437
Mediant 500 E-SBC

The device redirects the call to the first contact listed in the Contact header. If the
contact responds with a SIP response that is configured in the Reasons for Tel-to-IP
Alternative Routing table (see ''Alternative Routing Based on SIP Responses'' on page
401 ), the device tries to redirect the call to the next contact, and so on. If a contact
responds with a response that is not configured in the table, the device does not try to
redirect the call to the next contact and drops the call.
Note: If a SIP 401 or 407 response is received from a contact, the device does not try
to redirect the call to the next contact. Instead, the device continues with the regular
authentication process, as indicated by these response types.
24.5.4 PSTN Fallback
The PSTN Fallback feature enables the device to re-route a Tel-to-IP call to the legacy
PSTN using one of its trunks if the IP destination is unavailable. For example, if poor voice
quality is detected over the IP network, the device attempts to re-route the call to the
PSTN.
The steps for configuring alternative Tel-to-IP routing to the legacy PSTN are summarized
below.

To configure alternative Tel-to-IP routing to the legacy PSTN:
1. Configure an alternative routing rule in the Outbound IP Routing table with the same
call matching characteristics (e.g., phone number destination), but where the
destination is the IP address of the device itself.
2. Configure an IP-to-Tel routing rule in the Inbound IP Routing table to route calls
received from the device (i.e., its IP address) to a specific Trunk Group connected to
the PSTN. This configuration is necessary as the re-routed call is now considered an
IP-to-Tel call. For configuring IP-to-Tel routing rules, see ''Configuring the Inbound IP
Routing Table'' on page
394 .
Note: The PSTN Fallback feature is applicable only to digital interfaces (e.g., E1 / T1
trunks).