Classification and Routing of Registered Users

The device can classify incoming SIP dialog requests (e.g., INVITE) from registered users to an IP Group, by searching for the sender’s details in the registration database. The device uses the AOR from the From header and the URL in the Contact header of the request to locate a matching registration binding. The found registration binding contains information regarding the registered user, including the IP Group to which it belongs. (Upon initial registration, the Classification table is used to classify the user to a User-type IP Group and this information is then added with the user in the registration database.)

The destination of a dialog request can be a registered user and the device thus uses its registration database to route the call. This can be achieved by various ways such as configuring a rule in the IP-to-IP Routing table where the destination is a User-type IP Group or any matching user registered in the database ('Destination Type' is configured to All Users). The device searches the registration database for a user that matches the incoming Request-URI (listed in chronological order):

Unique Contact generated by the device and sent in the initial registration request to the serving proxy.
AOR. The AOR is originally obtained from the incoming REGISTER request and must either match both user part and host part (user@host) of the Request-URI, or only user part.
Contact. The Contact is originally obtained from the incoming REGISTER request.

If registrations are destined to the database (using the above rules), the device doesn't attempt to find a database match, but instead replies with a SIP 200 OK (used for Survivability). Once a match is found, the request is routed either to the contact received in the initial registration or (if the device identifies that the user agent is behind a NAT) to the source IP address of the initial registration.

You can configure (using the [SBCDBRoutingSearchMode] parameter) for which part of the destination Request-URI in the INVITE message the device must search in the registration database:

Only by entire Request-URI (user@host), for example, "4709@joe.company.com".
By entire Request-URI, but if not found, by the user part of the Request-URI, for example, "4709".

When an incoming INVITE is received for routing to a user and the user is located in the registration database, the device sends the call to the user's corresponding contact address specified in the database.

If the Request-URI contains the "tel:" URI or "user=phone" parameter, the device searches only for the user part.

You can also configure which URI parameters are excluded when the device compares the URIs of two incoming dialog-initiating SIP requests (e.g., INVITEs) to determine if they were sent from a user that is registered in the device's registration database. For example, you can configure the parameter to exclude ports from the comparison. For more information, see the description of the [SBCURIComparisonExcludedParams] parameter.