Dynamic Transport Protocol Change
The Oracle Communications Session Border Controller also uses the IP address and port in the Contact and Via headers. This is useful for cases when endpoints dynamically change transport protocols (TCP/UDP), and the port number used for sending an INVITE might not be the same one used to send a Register message.
If you do not enable this feature, when an endpoint registered with the Oracle Communications Session Border Controller used UDP for its transport protocol, a call fails if that endpoint subsequently initiates the call using TCP. The Oracle Communications Session Border Controller checks for the Layer 3 IP address and port, and it rejects the call if the port is changed.
With the new option reg-no-port-match added to the SIP interface configuration, the Oracle Communications Session Border Controller will not check the Layer 3 port in the INVITE and REGISTER messages.