Patent ID: 6785286
Filing Date: 2004-08-31
Classification: H04L,Y02D

Abstract:
A stackable multi-port communication unit for a packet-based data communication system and having a multiplicity of physical ports for the reception and dispatch of data in the form of packets, the unit including:switch logic for selecting for a packet at least one destination selected from a multiplicity of ports which include a logical port common to a specified group of said physical ports; cascade trunk logic, coupled to said switch logic, for determining, for the dispatch of a packet directed to said logical port, a selected port of said group of said physical ports; and monitoring logic for forwarding a copy of the packet; wherein said monitoring logic stores an indication of all the physical ports on the unit from which said copy can be forwarded by the monitoring logic and prevents the forwarding of said copy of the packet when any of those physical ports corresponds to the port selected by the cascade logic for the dispatch of said packet, whereby a packet which is forwarded from any of said specified group of physical ports is not duplicated by the monitoring logic.