Configuring Sip Response Codes For Alternative Routing Reasons - AudioCodes Mediant 3000 User Manual

Parameter
Cost Group
[IP2IPRouting_CostGroup]
33.4 Configuring SIP Response Codes for Alternative
Routing Reasons
The SBC Alternative Routing Reasons table lets you configure up to 20 SIP response
codes for call release (termination) reasons. If a call (outgoing SIP dialog-initiating
methods, e.g., INVITE, OPTIONS, and SUBSCRIBE messages) is released as a result of a
configured SIP code (provided in SIP 4xx, 5xx, and 6xx), the device attempts to locate an
alternative route for the call in the IP-to-IP Routing table. Alternative routing rules are
configured with the 'Alternative Route Options' parameter set to Alt Route Ignore Inputs
or Alt Route Consider Inputs (see ''Configuring SBC IP-to-IP Routing Rules'' on page
603).
Typically, the device performs alternative routing when there is no response at all to an
INVITE message. This is done after a user-defined number of INVITE re-transmissions,
configured by the SIPMaxRtx parameter. In such a scenario, the device issues itself the
SIP response code 408 (Request Timeout). Alternative routing is only done if you have
configured this response code in the SBC Alternative Routing Reasons table.
You can also configure alternative routing for the following proprietary response codes, if
configured in the table, that are issued by the device itself:

805 IP Profile Call Limit: The device generates this response code when Call
Admission Control (CAC) limits (such as maximum concurrent calls) are exceeded for
an IP Group (or SRD). The CAC rules are configured in the Admission Control table
(see ''Configuring Admission Control'' on page 587). When this occurs, the device
sends a SIP 480 (Temporarily Unavailable) response to the SIP entity. In such a
scenario, an alternative route configured in the IP-to-IP Routing table can be used.

806 Media Limits Exceeded: The device generates this response code when the call
is terminated due to crossed thresholds of QoE metrics such as MOS, packet delay,
and packet loss (configured in the Quality of Experience Profile table) and/or media
bandwidth (configured in the Bandwidth profile table). When this occurs, the device
sends a SIP 480 (Temporarily Unavailable) response to the SIP entity. This is
configured by 1) assigning an IP Group a QoE and/or Bandwidth profile that rejects
calls if the threshold is crossed, 2) configuring 806 in the SBC Alternative Routing
User's Manual
Assigns a Cost Group to the routing rule for determining the cost of the
call.
By default, no value is defined (None).
For configuring Cost Groups, see ''Configuring Cost Groups'' on page
275.
Notes:

To implement LCR and its Cost Groups, you must enable LCR for the
Routing Policy assigned to the routing rule (see ''Configuring SBC
Routing Policy Rules'' on page 616). If LCR is disabled, the device
ignores the parameter.

The Routing Policy also determines whether matched routing rules
that are not assigned Cost Groups are considered as a higher or
lower cost route compared to matching routing rules that are
assigned Cost Groups. For example, if the 'Default Call Cost'
parameter in the Routing Policy is configured to Lowest Cost, even if
the device locates matching routing rules that are assigned Cost
Groups, the first-matched routing rule without an assigned Cost
Group is considered as the lowest cost route and thus, chosen as the
preferred route.
614
Description
Document #: LTRT-89730
Mediant 3000