AudioCodes Mediant 1000 User Manual page 201

SIP User's Manual
Note that for this table to take precedence over a Proxy for routing calls, set the parameter
PreferRouteTable to 1. The device checks the 'Destination IP Address' field in this table for
a match with the outgoing call. A Proxy is used only if a match is not found.
Possible uses for Tel-to-IP routing include the following:
Fallback to internal routing table if there is no communication with the Proxy servers.
Call Restriction (when Proxy isn't used): rejects all outgoing Tel-to-IP calls that are
associated with the destination IP address 0.0.0.0.
IP Security: When the IP Security feature is enabled (SecureCallFromIP = 1), the
device accepts only those IP-to-Tel calls with a source IP address defined in the 'Tel
to IP Routing' table.
Filter Calls to IP: When a Proxy is used, the device checks the 'Tel to IP Routing' table
before a telephone number is routed to the Proxy. If the number is not allowed
(number isn't listed or a Call Restriction routing rule is applied), the call is released.
Always Use Routing Table: When this feature is enabled (AlwaysUseRouteTable = 1),
even if a Proxy server is used, the SIP URI host name in the sent INVITE message is
obtained from this table. Using this feature, you can assign a different SIP URI host
name for different called and/or calling numbers.
Assign Profiles to destination addresses (also when a Proxy is used).
Alternative Routing (when a Proxy 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 into two IP addresses. The call is sent to the
alternative destination when one of the following occurs:
•
No ping to the initial destination is available, poor QoS (delay or packet loss,
calculated according to previous calls) is detected, or a DNS host name is not
resolved. For detailed information on Alternative Routing, refer to ''Configuring
Alternative Routing (Based on Connectivity and QoS'' on page 415.
•
A release reason defined in the 'Reasons for Alternative Tel to IP Routing' table is
received (refer to ''Reasons for Alternative Routing'' on page 209).
Alternative routing (using this table) is commonly implemented when there is no response
to an INVITE message (after INVITE retransmissions). The device then issues an internal
408 'No Response' implicit release reason. If this reason is included in the 'Reasons for
Alternative Routing' table, the device immediately initiates a call to the redundant
destination using the next matched entry in the 'Tel to IP Routing' table. Note that if a
domain name in this table is resolved into two IP addresses, the timeout for INVITE
retransmissions can be reduced by using the parameter 'Number of RTX Before Hotswap'.
Version 5.4 201
3. Web-Based Management
May 2008