Patent ID: 6788681
Filing Date: 2004-09-07
Classification: H04L

Abstract:
A system of providing communication between a first and a second Local Area Network (LAN), said first and second LANs interconnected by a connectionless network, said system comprising:a first network interface connecting said first LAN to said connectionless network, said first receiving device for: receiving conventional LAN data frames; determining an address of a second network interface responsive to destination information in said received conventional LAN data frames, said second network interface connecting said second LAN to said connectionless network; and encapsulating said conventional LAN data frames received at said first network interface with said address of said second network interface; a router for routing said conventional LAN data frames encapsulated with said address to said second network interface over said connectionless network; said second network interface connecting said second LAN to said connectionless network, said second network interface for: receiving conventional LAN data frames encapsulated with said address; re-generating said conventional LAN data frames from said conventional LAN data frames encapsulated with said address; and transmitting said re-generated conventional LAN data frames to said second LAN; and wherein said determining comprises: determining an identifier uniquely identifying a virtual private network (VPN) comprising at least said first and second LANs; accessing a routing table stored at said first network interface; where possible, retrieving, from said routing table a unique address of said second network interface responsive to a destination address stored in said received LAN data frames and said determined identifier, said unique address comprising an IP address; and if said routing table does not contain said unique address for said destination information, retrieving a multicast address, said multicast address representative of all LANs forming part of said VPN and comprises an IP multicast address; and wherein said encapsulating comprises encapsulating said conventional LAN data frames with said determined identifier and one of said unique address of said second network interface and said multicast address.