lThe NAT device uses a configurable aging timer for mapping entries. Generally, the reregistration time of a SIP UE is longer than the aging time of address mapping entries on the NAT device. The SE1000, being a heuristic device, can learn the addresses of UE-initiated packets after NAT. After the address mapping entry for a SIP UE on the NAT device ages out, if the NAT device receives a service packet originating from a SIP UE, the NAT device will be unable to find an address mapping entry and therefore will discard the packet. As a result, the requested service is interrupted.
