Inbound HMR Challenge

Because inbound manipulations take place before the message reaches the core of Oracle Enterprise Communications Broker (OECB) SIP processing, the SIP proxy takes the manipulated header as directly received from the client. This can cause problems for requests leaving the OECB for the UAC because the dialog does not match the initial request sent.

The unmodified header must be cached because for any subsequent request (For example, a BYE originating from the terminator. See the following diagram.) the OECB might need to restore the original value, enabling the UAC to identify the message correctly as being part of the same dialog. For out-of-dialog requests (when the To, From, or Call-ID headers are modified) the original header is stored in the dialog when the msg-type out-of-dialog is used.

The OECB performs the restoration of original headers outside of SIP manipulations. There are no manipulation rules to configure for restore the header to their original context. The OECB recognizes that the headers are modified, and restores them to their original state prior to sending the message out. Restoration takes place prior to outbound manipulations so that any outbound manipulation can those headers after they are restored.