Patent ID: 8018941

Claim:
A method for disassociating routing tables and forwarding tables from routers used in a network comprising: implementing a route server running a dynamic routing protocol and having a full route table for the network, which may receive prefix requests from any router in the network; implementing a helper router having a full route table for the network, wherein a helper router may receive packets from, and forward those packets on behalf of any router in the network; receiving a packet at a constrained router running a dynamic routing protocol, wherein a router is constrained if the router's memory capacity cannot store the full route table for the network; performing a route lookup at the constrained router for the destination address of the received packet and not finding a match other than a default route; generating a prefix-request at the constrained router; transmitting the prefix-request containing the destination address of the received packet from the constrained router to the route server contemporaneous with forwarding the received packet at the constrained router and subsequently received packets for that destination address to the helper router where a forwarding look-up is performed; at the route server, performing a longest-match on the destination address in the prefix-request; forwarding the packet(s) received at the helper router to an egress router; and advertising a route announcement via a dynamic routing protocol containing a prefix from the route server in response to the prefix-request from the constrained router wherein the route announcement identifies an optimal next hop for the received packet.