Configuring Sip Response Codes For Alternative Routing Reasons - AudioCodes Mediant 500 E-SBC User Manual

Parameter
Cost Group
[IP2IPRouting_CostGroup]
CLI: cost-group
28.5.4 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
477).
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 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 465). 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
Reasons table and 3) configuring an alternative routing rule.
Notes:
•
If the device receives a SIP 408 response, an ICMP message, or no response,
alternative routing is still performed even if the SBC Alternative Routing Reasons
table is not configured.
•
SIP requests belonging to an SRD or IP Group that have reached the call limit
(maximum concurrent calls and/or call rate) as configured in the Call Admission
table are sent to an alternative route if configured in the IP-to-IP Routing table for
the SRD or IP Group. If no alternative routing rule is located, the device
automatically rejects the SIP request with a SIP 486 (Busy Here) response.
The following procedure describes how to configure the SBC Alternative Routing Reasons
table in the Web interface. You can also configure this table using the table ini file
User's Manual
Assigns a Cost Group to the routing rule for determining the
cost of the call. To configure Cost Groups, see ''Configuring
Cost Groups'' on page 228.
By default, no Cost Group is defined.
486
Mediant 500 E-SBC
Description
Document #: LTRT-10427