Method and apparatus for controlling the flow of variable-length packets through a multiport switch

An apparatus for controlling a flow of variable-length packets through a multiport switch comprising:

• means for receiving a packet that is part of said flow of variable-length packets wherein said packet includes packet-specific header information related to layer 3 and layer 4 protocols;
• memory having searchable registers that store flow-specific packet forwarding information including application protocol information contained in said layer 4 protocol;
• means for locating, within said memory, flow-specific packet forwarding information specific to said flow of variable-length packets that said received packet is part of, based at least partially on said application protocol information;
• means, formed in circuitry that is specific to packet flow control, for comparing the time said received packet arrived in said switch to the time that said flow-specific packet forwarding information specific to said flow was previously accessed by another packet to determine if a pre-established time interval has expired;
• means, formed in circuitry that is specific to packet flow control, for comparing a credit bucket value that indicates a maximum size packet to the size of said received packet and for forwarding said received packet when the size of said received packet is less than or equal to said credit bucket value that indicates said maximum size packet, and for dropping or limiting said forwarding of said received packet when said received packet is larger than said credit bucket value that indicates said maximum size packet;
• and
• means for decrementing said credit bucket value each time a packet from said flow of variable-length packets is forwarded and for refreshing said credit bucket value back to a pre-established credit bucket value each time it is determined that said pre-established time interval has expired.

A method of controlling the flow of variable-length packets through a transmission control protocol, TCP, and internet protocols, IP, compatible multiport switch wherein said variable-length packets include layer 2, layer 3, and layer 4 header information comprising the steps of:

• receiving a packet of a particular length within said multiport switch;
• stripping layer 2 header information from said packet;
• accessing a memory that contains flow-specific information;
• utilizing layer 3 and layer 4 header information from said received particular length packet to look-up flow-specific information in said accessed memory;
• comparing said flow-specific information to the length of said particular length packet and to a clock value that is representative of the time that said packet was received by said multiport switch;
• and
• forwarding said particular length packet through said multiport switch if the length of said particular length packet does not exceed a maximum packet length as determined by a credit bucket indicator included within said flow-specific information.

A method of controlling the flow of variable-length packets on data links connected to a multiport switch comprising steps of:

• receiving a packet that includes packet-specific header information at said multiport switch;
• accessing a memory that contains forwarding information, said forwarding information including bandwidth management information;
• searching said memory based on said packet-specific header information of said packet;
• locating, in said memory, forwarding information that is related to said packet;
• extracting bandwidth management information from said forwarding information that is related to said packet, and isolating a time select vector that indicates significant bits of a system counter and determines a pre-established time interval, wherein said bandwidth management information includes a bandwidth consumption limit that is relevant to forwarding said packet;
• comparing said extracted bandwidth management information to said packet;
• forwarding said packet within said multiport switch when said comparison indicates that forwarding said packet will not exceed said bandwidth consumption limit;
• and
• dropping said packet from said multiport switch or tagging said packet with an adjusted priority before forwarding of said packet within said multiport switch when said comparison indicates that forwarding said packet will exceed said bandwidth consumption limit.