Patent ID: 6178171
Filing Date: 2001-01-23
Classification: H04L

Abstract:
A method comprising the steps of:issuing a route resolution request from a route resolution protocol client residing in a data processing device of a first ISO layer-3 subnetwork in response to communication with a destination host of a second ISO layer-3 subnetwork communicating with said first ISO layer-3 subnetwork through one or more routers and forwarding said route resolution request toward said destination host, such forwarding comprising the steps of:determining if a current router of said one or more of routers connects to said second layer-3 subnetwork, andsending said route resolution request to a next router of said one or more routers toward said destination host when said current router does not connect to said second layer-3 subnetwork:obtaining a Media Access Control (MAC) address, ATM address and a Route Information Field (RIF) segment associated with said destination host in response, to said route resolution request by a route resolution protocol server residing in one or more routers connecting a plurality of ISO layer-3 subnetworks, said first ISO layer-3 subnetwork and said second ISO layer-3 subnetwork being among said plurality of ISO layer-3 subnetworks, the step of obtaining comprising the steps of:responding to said route resolution request by determining a MAC address and an ATM address associated with said destination host by an egress route resolution protocol server, said egress route resolution protocol server being a route resolution protocol server of a router attached to said second ISO layer-3 subnetwork, said last-mentioned router attached to said second ISO layer-3 subnetwork being among said one or more routers:sending an route resolution reply in one or more route resolution packets to said route resolution protocol client by said egress route resolution protocol server, said route resolution reply including said MAC address, said ATM address and a RIF segment associated with said destination host, and forwarding said route resolution reply toward said route resolution client. such forwarding comprising the steps of:determining if a current router of said one or more routers, connects to said first layer-3 subnetwork; andsending said route resolution reply to a next router of said one or more routers toward said route resolution client when said current router does not connect to said first layer-3 subnetwork; generating a virtual route descriptor:merging a RIF segment associated with said route resolution client with a RIF segment including said RIF segment associated with said destination host and interposing said virtual route descriptor between said RIF segment associated with said route resolution client and said RIF segment containing said RIF segment associated with said destination host included in said route resolution reply;registering said generated virtual route descriptor with a data processing device in said first ISO layer-3 subnetwork, and binding said virtual route descriptor with said ATM address; andsending to said destination host one or more data packets which include said MAC address by establishing a Virtual Channel Connection (VCC) by a LAN Switch coupled to a first ELAN to a device attached to a second ELAN wherein said second ELAN is in said second ISO layer-3 subnetwork, the step of establishing a VCC comprising the steps of:issuing an Emulated LAN Address Resolution Protocol request (LEARPRequest) by said LAN Switch in response to said data packets including said MAC address;creating a data-direct VCC to said ATM address associated with said destination host, said ATM address being received in response to said LEARPRequest by said LAN Switch; andtransmitting said one or more data packets to said ATM address via said data-direct VCC.