About Loose Routing

According to RFC 3261, a proxy is loose routing if it follows the procedures defined in the specification for processing of the Route header field. These procedures separate the destination of the request (present in the Request-URI) from the set of proxies that need to be visited along the way (present in the Route header field).

When the SIP NAT’s route home proxy field is set to enabled, the Oracle® Enterprise Session Border Controller looks for a session agent that matches the home proxy address and checks the loose routing field value. If the loose routing is:

• enabled—A Route header is included in the outgoing request in accordance with RFC 3261.
• disabled—A Route header is not included in the outgoing request; in accordance with the route processing rules described in RFC 2543 (referred to as strict routing). That rule caused proxies to destroy the contents of the Request-URI when a Route header field was present.

Whether loose routing field is enabled is also checked when a local policy ‘s next hop value matches a session agent. Matching occurs if the hostname or the session agent’s IP address field value corresponds to the next hop value. If loose routing is enabled for the matching session agent, the outgoing request retains the original Request-URI and Route header with the next hop address.