AudioCodes Mediant 1000B User Manual page 400

Depending on configuration, the alternative routing is done using one of the following
configuration entities:

Outbound IP Routing Rules: You configure alternative routing rules for a specific
routing rule in the Outbound IP Routing table. If the destination of the "main" routing
rule is unavailable, the device searches the table for the next matching rule (e.g.,
destination phone number), and if available attempts to re-route the call to the IP
destination configured for this alternative routing rule. For more information on
configuring alternative Tel-to-IP routing rules, see ''Configuring Outbound IP Routing
Table'' on page
the device uses the first available alternative routing rule to re-route the initial,
unsuccessful Tel-to-IP call destination:
Table 24-5: Alternative Routing based on SIP Response Code Example
Main Route
Alternative Route #1
Alternative Route #2

Proxy Sets: Proxy Sets are used for Server-type IP Groups (e.g., an IP PBX or
proxy), which define the address (IP address or FQDN) of the server (see ''Configuring
Proxy Sets'' on page 272). As you can configure multiple IP destinations per Proxy
Set, the device supports proxy redundancy, which works together with the alternative
routing feature. If the destination of a routing rule in the Outbound IP Routing table is
an IP Group, the device routes the call to the IP destination configured for the Proxy
Set associated with the IP Group. If the first IP destination of the Proxy Set is
unavailable, the device attempts to re-route the call to the next proxy destination, and
so on until an available IP destination is located. To enable the Proxy Redundancy
feature for a Proxy Set, set the IsProxyHotSwap parameter to 1 and the
EnableProxyKeepAlive parameter to 1.
When the Proxy Redundancy feature is enabled, the device continually monitors the
connection with the proxies by using keep-alive messages (SIP OPTIONS). The
device sends these messages every user-defined interval (ProxyKeepAliveTime
parameter). If the first (primary) proxy in the list replies with a SIP response code that
you have also configured by the 'Keep-Alive Failure Responses' parameter, the device
considers the Proxy as down; otherwise, the device considers the proxy as "alive". If
the proxy is still considered down after a user-defined number of re-transmissions
(configured by the HotSwapRtx parameter), the device attempts to communicate
(using the same INVITE) with the next configured (redundant) proxy in the list, and so
on until an available redundant proxy is located. Once an available proxy is located,
the device can operate in one of the following modes (configured by the
ProxyRedundancyMode parameter):
•
Parking mode: The device continues operating with the redundant proxy (now
active) until the next failure occurs, after which it switches to the next redundant
proxy.
•
Homing mode: The device always attempts to operate with the primary proxy. In
other words, it switches back to the primary proxy whenever it's available again.
If none of the proxy servers respond, the device goes over the list again.
User's Manual
383. The table below shows an example of alternative routing where
Destination
IP Destination
Phone Prefix
40 10.33.45.68
40 10.33.45.70
40 10.33.45.72
Mediant 1000B Gateway & SBC
SIP Response
408 Request
Timeout
486 Busy Here
200 OK
400
Rule Used?
No
No
Yes
Document #: LTRT-27034