SIP NAT Bridge Configuration Scenarios
You can configure the SIP NAT bridge functionality in a many-to-one or a one-to-one relationship. For example, multiple customer SIP NATs can be tied to a single backbone SIP NAT, or a single customer SIP NAT can be tied to a single backbone SIP NAT.
You might need to use several SIP NATs on the customer side while using only one on the backbone side in a many-to-one relationship. Or you might configure one SIP NAT on the backbone side for every one that you configure on the customer side in a one-to-one relationship.
You can route all customer side SIP NAT requests to the corresponding backbone SIP NAT regardless of the Request URI. If a request arrives from the customer network with a Request URI that does not match the customer SIP NAT external address or the local policy that would route it to the backbone SIP NAT; the route home proxy value is used.