Bridges and other layer-two devices for forwarding MAC frames
AssigneeHewlett-Packard Company
InventorsMasoud Khansari, Derek Lam
Life of this patent
Estimating the term…
Abstract
A bridge or other transparent layer-two device uses a simple protocol to filter duplicate frames and learn about nodes connected to a bridged local area network. Using the simple protocol, the bridge or other layer-two device does not need to run a Spanning Tree algorithm.
Claims24
In a transparent layer-two device of a local area network, a method of handling a MAC frame received on an inbound port, the method comprising:
- determining whether the frame was previously received on a port other than the inbound port;
- discarding the frame if the frame was previously received on a port other than the inbound port;
- further filtering the frame if the frame was not discarded;
- and
- forwarding the frame if the frame was not filtered out.
A layer-two device for a network, the device comprising:
- a plurality of ports for receiving MAC frames;
- means for determining whether an inbound frame received on an inbound port was previously received on a port other than the inbound port;
- discarding the inbound frame if the inbound frame was previously received on a port other than the inbound port;
- further filtering the inbound frame if the inbound frame was not discarded;
- and
- forwarding the inbound frame if the inbound frame was not filtered out.
A layer-two device for a network for a computer network, the device comprising:
- a plurality of ports;
- a controller;
- and
- computer memory;
- the computer memory being encoded with a program for instructing the controller to examine the source address of a frame received on an inbound port;
- determine whether the source address is in a Filtering database;
- forward the frame if the source address is not in the Filtering database;
- determine whether the frame was previously received on a port other than the inbound port if the source address is in the Filtering database;
- discard the frame if the frame was previously received on a port other than the inbound port;
- further filter the frame if the frame was not discarded;
- and forward the frame if the frame was not filtered out.
An article of manufacture for a layer-two device of a network, the layer-two device including a plurality of ports and a processor, the article comprising:
- computer memory
- a program encoded in the memory, the program, when executed, instructing the controller to examine the source address of a frame received on an inbound port;
- determine whether the source address is in a Filtering database;
- forward the frame if the source address is not in the Filtering database;
- determine whether the frame was previously received on a port other than the inbound port if the source address is in the Filtering database;
- discard the frame if the frame was previously received on a port other than the inbound port;
- and perform a forwarding routine if the frame was not discarded;
- the forwarding routine being performed by examining a destination address of the frame;
- finding a database entry having the same destination address as the frame;
- forwarding the frame to all of the ports except ports that have seen the frame if an entry is not found;
- discarding the frame if an entry was found and the inbound port is the same as a destination address port;
- and forwarding the frame to the destination address port if an entry was found and the inbound port is not the same as a destination address port.
A layer-two device for a local area network, the device comprising a processor for handling a MAC frame received on an inbound port by determining whether the frame was previously received on a port other than the inbound port, and discarding the frame if the frame was previously received on a port other than the inbound port.
Dependencies are inferred from the claim text.