AudioCodes Mediant 500 E-SBC, User Manual

Page: 480 / 920

User's Manual 480 Document #: LTRT-10437
Mediant 500 E-SBC
28.5 Routing SBC
This section describes the configuration of the routing entities for the SBC application.
These include the following:

Classification rules - see ''Configuring Classification Rules'' on page 480

Message Condition rules - see ''Configuring Message Condition Rules'' on page 486

IP-to-IP routing rules - see ''Configuring SBC IP-to-IP Routing Rules'' on page 487

Alternative routing reasons - see ''Configuring SIP Response Codes for Alternative
Routing Reasons'' on page
497
28.5.1 Configuring Classification Rules
The Classification table lets you configure up to 100 Classification rules. A Classification
rule classifies incoming SIP dialog-initiating requests (e.g., INVITE messages) to an IP
Group from where the SIP dialog request was received. The identified IP Group is then
used in the manipulation and routing processes. Classification rules also enhance security
by allowing you to create a SIP access list, whereby classified calls can be denied (i.e.,
blacklist) or allowed (i.e., whitelist).
Configuration of Classification rules includes two areas:

Rule: Defines the matching characteristics of the incoming IP call (e.g, source SIP
Interface and IP address).

Action: Defines the action that is done if the incoming call matches the characteristics
of the rule (i.e., classifies the call to the specified IP Group).

The device searches the table from top to bottom for the first rule that matches the
characteristics of the incoming call. If it finds a matching rule, it classifies the call to the
IP Group configured for that rule.
The Classification table is used to classify incoming SIP dialog requests only if the
following classification stages fail:
1. Classification Stage 1 - Registered Users Database: The device searches its
registration database to check if the incoming SIP dialog arrived from a registered
user:
•
Compares the SIP Contact header of the received SIP dialog to the Contact of
the registered user.
•
Compares the URL in the SIP P-Asserted-Identity/From header to the registered
address-of-record (AOR).
If this stage fails, the device proceeds to classification based on Proxy Set.
2. Classification Stage 2 - Based on Proxy Set: If the database search fails, the
device performs classification based on Proxy Set. This classification is applicable
only to Server-type IP Groups and is done only if classification based on Proxy Set is
enabled (see the 'Classify By Proxy Set' parameter in the IP Group table in
''Configuring IP Groups'' on page 263). The device checks whether the incoming
INVITE's IP address (if host name, then according to the dynamically resolved IP
address list) is configured for a Proxy Set (in the Proxy Set table). If such a Proxy Set
exists, the device classifies the INVITE to the IP Group that is associated with the
Proxy Set. The Proxy Set is assigned to the IP Group in the IP Group table.
If classification based on Proxy Set fails (or classification based on Proxy Set is
disabled), the device proceeds to classification based on the Classification table.