About SIP Port Mapping

You might need to provide a unique signaling transport address for each registered endpoint for admission control, if required by your softswitch vendor. If you have questions about your softswitch, contact the vendor for assistance.

When a Oracle® Enterprise Session Border Controller resides between the endpoints and the softswitch, the softswitch sees the same transport address (that of the Oracle® Enterprise Session Border Controller) for all endpoints. By allocating a unique UDP port for each endpoint, the Oracle® Enterprise Session Border Controller provides each of them a unique transport address.

The following example illustrates the SIP port mapping feature.

The diagram shows UA1, UA2, and UA3 are endpoints within the access network and that the SIP interface for the access network is 172.16.0.15:5060. On the provider network, the SIP interface is at 192.168.24.15, with the SIP port mapping feature enabled. The softswitch/registrar is also located on the provider network at 192.168.24.90:5060.

The diagram shows that port 2001 on the provider network is allocated to UA1 on the access network, port 2002 is allocated to UA2, and port 2003 is allocated to UA3. Because of this allocation, all SIP signaling messages sent from the endpoints in the access network to the softswitch on the provider network travel through an allocated signaling port. For example, all signaling messages between UA1 and the softswitch use 192.168.24.15:2001 as the transport address.