Patent ID: 7289496
Filing Date: 2007-10-30
Classification: H04L

Abstract:
1. A network unit which is capable of use in a cascaded stack of network units and includes: a multipticity of ports for receiving and forwarding addressed data packets, a switching engine for directing received packets to at least one port in accordance with address data in the packets; at least two cascade ports for receiving packets from and sending packets to adjacent network units in the cascaded stack; means for detecting an operational failure between this network unit and an adjacent network unit in the stack and for controlling the switching engine to redirect packets which would otherwise be sent from a particular port to that adjacent network unit to be forwarded from another port whereby to be sent to a different network unit in the stack; and wherein this network unit is responsive to control data indicating an operational failure between two other units in a stack to enter a bypass mode to cause packets received at a cascade port and intended for further transmission on the cascade to be forwarded without being re-directed by the switching engine.