Method and apparatus for flow control on a switched CSMA/CD network implementing BLAM

An apparatus for providing improved flow control over a node on a switched network by transmitting a packet which is either self-addressed or addressed to a null address such that said packet is not received by any node attached to a port, comprising:

• means for triggering a node to transmit immediately when buffer space becomes available;
• means for transmitting said packet to said port that is in the midst of a backoff period;
• and
• means for causing said backoff period to be reset zero upon reception of said packet;
• wherein said node begins transmitting immediately.

A method for providing improved flow control on a CSMA/CD network including at least one switch having a MAC relay entity and a plurality of remote MAC entities, comprising the steps of:

• monitoring traffic from all of said remote MAC entities at a switch or bridge with said MAC relay entity;
• notifying said MAC relay entity that one or more of said remote MAC entities have excess traffic;
• instructing a local MAC entity with said MAC relay entity to exert or not exert flow control at one or more of said remote MAC entities based on traffic demands placed on said remote MAC entities;
• setting a backoff period with said local MAC entity if said MAC relay entity instructs said local MAC entity to assert flow control, wherein during said backoff period said local MAC entity may either declare a collision for all packets or alternatively declare a collision for specific packets having specific destination addresses at which traffic is congested;
• and
• resetting said backoff period to zero when said MAC relay entity indicates that it is no longer necessary to exert flow control before said backoff period has expired.

An apparatus for providing improved flow control on a CSMA/CD network including at least one switch having a MAC relay entity and a plurality of remote MAC entities, said apparatus comprising:

• a MAC relay entity for monitoring traffic from all of said remote MAC entities at a switch or bridge, said MAC relay entity notifying a local MAC relay entity that one or more of said remote MAC entities have excess traffic;
• means for instructing said local MAC entity to exert or not exert flow control based on traffic demands placed on said remote MAC entities;
• means for setting a backoff period if said MAC relay entity instructs said local MAC entity to exert flow control, wherein during said backoff period said local MAC entity may either declare a collision for all packets or alternatively declare a collision for specific packets having specific destination addresses at which traffic is congested;
• and
• means for resetting said backoff period to zero when said MAC relay entity indicates that it is no longer necessary to exert flow control before said backoff period has expired.