Patent ID: 7903672

Claim:
A system comprising: a subscriber network comprising: a firewall device; a network telephony device that sends registration requests to a network telephony service provider (NTSP) network via the firewall device, wherein the registration requests maintain an open logical pinhole within the firewall device; a service provider network positioned between the subscriber network and the NTSP network, the service provider network including a layer three (L3) provider edge router; a session border controller (SBC) of the NTSP network that responds to registration requests from the network telephony device, wherein the SBC operates as a gateway to the NTSP network, wherein the firewall device of the subscriber network is positioned between the network telephony device and the service provider network, wherein the layer three (L3) provider edge router of the service provider network is positioned between the firewall device and the SBC of the NTSP network, and wherein the layer three (L3) provider edge router comprises: a routing engine configured to maintain routing data that reflects a topology of the service provider network; a plurality of interface cards to receive packets on the service provider network, wherein each of the interface cards includes a forwarding component programmed to forward the packets, wherein at least a portion of the packets include registration requests sent by the network telephony device and registration responses sent by the SBC; and a signaling processor that executes within the routing engine to respond to a filtered portion of the intercepted requests on behalf of the SBC by sending to the network telephony device autonomous responses mimicking the responses sent by the SBC and forward an unfiltered portion of the intercepted requests to the SBC via the service provider network, wherein the unfiltered portion includes a number of the requests sufficient to maintain the registration of the network telephony device with a registrar of the NTSP network, wherein each of the plurality of interface cards includes a corresponding registration interceptor module to intercept the registration requests from the network telephony device to the NTSP network and intercept registration responses from the SBC to the network telephony device, each of the registration interceptor modules configured to inspect the packets to determine those packets that form part of the registration requests or the registration responses, forward the packets to the signaling processor of the routing engine that form part of the requests and responses and forward any other ones of the packets to the forwarding components of the interface cards to be forwarded onto the NTSP network.