Patent ID: 6801527
Filing Date: 2004-10-05
Classification: H04L

Abstract:
A stack composed of a plurality of network units each of which has a multiplicity of ports for receiving and forwarding addressed data packets, wherein:(a) each network unit includes a forwarding engine for directing a packet received at a port of the unit to at least one other port of the network unit; (b) a communication trunk is connected to a multiplicity of trunk ports distributed among said network units; (c) a cascade connects said network units by way of at least one cascade port of each network unit; (d) each network unit includes a respective first register having at least one storage location for each unit which has at least one of said trunk ports; (e) each network unit includes a respective second register having at least one storage location for each port that is on that unit and is connected to said communication trunk; (f) a forwarding engine of a respective network unit makes a determination whether a packet is destined for said trunk and in response thereto accesses a storage location in said respective first register by hashing data within said packet to obtain an identification of one of said network units, said forwarding engine directing the packet to said trunk by way of a trunk port of said respective network unit when said respective network unit has at least one trunk port and said identification corresponds to said respective network unit, and said forwarding engine directing the packet to said cascade when said identification corresponds to a unit other than said respective network unit; and (g) said forwarding engine of a respective network unit accesses said respective second register to determine an egress port for a packet destined for forwarding to said trunk from said respective network unit.