Patent ID: 6636516
Filing Date: 2003-10-21
Classification: H04L

Abstract:
A router for building a virtual private network (VPN) through an ATM (asynchronous transfer mode) network configured as part of a public switched packet network, the router comprising:a connection setup table having a plurality of entries, each entry including a pair of internet protocol (IP) addresses respectively identifying source and destination nodes of the virtual private network, a quality-of-service parameter, an ATM address field, and a virtual connection (VC) field; and control circuitry for (a) receiving a VPN packet and detecting a corresponding entry in said table that contains IP addresses of the packet and making a search through the corresponding table entry for contents of the ATM address field and the VC field thereof, (b) appending an IP header to the VPN packet, if said ATM address field contains no data, to formulate an address resolution request packet and forwarding the packet to said public switched packet network, (c) receiving an address resolution reply packet therefrom and storing a destination ATM address contained in the reply packet into said ATM address field, and (d) if said ATM address field contains a destination ATM address and said VC field contains no data, establishing a virtual connection to the destination ATM address according to the quality-of-service parameter of the corresponding table entry and storing a connection identifier identifying the established virtual connection in said VC field, and if said VC field contains a connection identifier, forwarding said VPN packet over an established virtual connection identified by the connection identifier.