Administrators define routing policies for forwarding and routing data packets. A routing policy overrides routing protocol decisions. Policy-based routing includes a mechanism for selectively applying policies based on access list, packet size, or other criteria. The routing policy can include actions such as routing packets based on user-defined routes.
Session Manager uses routing policy data in the following manner:
First, Session Manager tries to match the domain to one of the authoritative domains.
If Session Manager is authoritative for the domain, then the Session Manager tries to match the digit pattern.
If a digit pattern is not matched, Session Manager tries to use the regular expression table.
If no regular expression match is found, Session Manager sends the request to a Session Manager-provisioned outbound proxy.
If no outbound proxy has been administered for the Session Manager and Session Manager is not authoritative for the domain, then Session Manager routes the request to the destination in the request-URI.
If the request-URI does not contain an IP address, then Session Manager uses DNS or the Local Host Name Resolution table to determine where to route the request.
If the Session Manager cannot resolve the hostname to an IP address, the call fails.
