US 7,590,074 B1
Method and apparatus for obtaining routing information on demand in a virtual private network
Lakshminath Dondeti, Chelmsford, Mass. (US); Donald Fedyk, Groton, Mass. (US); Ravi Ravindran, Ottawa (Canada); and Hong Zhang, Kanata (Canada)
Assigned to Nortel Networks Limited, St. Laurent, Quebec (Canada)
Filed on Dec. 02, 2004, as Appl. No. 11/1,815.
Int. Cl. H04L 12/28 (2006.01)
U.S. Cl. 370—254  [370/401] 19 Claims
OG exemplary drawing
 
13. A network element, comprising:
at least one communication port;
at least one processor configured to control the dissemination of routing information over the communication port, said at least one processor being configured to implement control logic designed to enable the network element to receive first intra-site reachability information about a first Virtual Private Network (VPN) site associated with a first gateway, store the first intra-site reachability information for distribution to a second gateway on demand, and in operation, when the second gateway needs access to the first intra-site reachability information, transmit at least a portion of the first intra-site reachability information to the second gateway as the first intra-site reachability information is needed by the second gateway:
(1) in response to receipt of a data packet from the second gateway that is required to be addressed using the first intra-site reachability information; or
(2) in response to receipt of a request for the specific first intra-site reachability information from the second gateway;
wherein a portion of the first intra-site reachability information may be selectively populated to the second gateway after the portion of the first intra-site reachability information is needed by the gateway rather than having the first intra-site reachability information automatically populated to the second gateway as the first intra-site reachability information becomes known by the network element.