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A content addressable memory (CAM or L3 Table) contains flow information for each active flow of packets passing through a given node of a data communications network. The CAM has associated with each entry (corresponding to each active flow) a packet counter, a byte counter, a token bucket and a co

A content addressable memory (CAM or L3 Table) contains flow information for each active flow of packets passing through a given node of a data communications network. The CAM has associated with each entry (corresponding to each active flow) a packet counter, a byte counter, a token bucket and a contract value. Each flow is assigned one of a plurality of output queues and optionally at least one output threshold value. A token bucket algorithm is employed on each flow to determine whether packets from that flow exceed the contract value. Such packets may be dropped or optimally modified to reflect an alternate output queue and/or alternate threshold before being sent to the selected output queue for transmission from the node. In another aspect an access control list CAM (ACLCAM) contains masked flow information. The ACLCAM provides an index to internal token bucket counters and preconfigured contract values of an aggregate flow table which becomes affected by the packet statistics. In this way flows are aggregated for assignment of output queues and thresholds, possible dropping and possible modification of packets. In another aspect the CAM contains active flow information, the ACLCAM and the aggregate flow table are combined in one system and used to produce in parallel a pair of traffic rate limiting and prioritizing decisions for each packet. The two results are then resolved to yield a single result.

대표청구항 ▼

A content addressable memory (CAM or L3 Table) contains flow information for each active flow of packets passing through a given node of a data communications network. The CAM has associated with each entry (corresponding to each active flow) a packet counter, a byte counter, a token bucket and a co

A content addressable memory (CAM or L3 Table) contains flow information for each active flow of packets passing through a given node of a data communications network. The CAM has associated with each entry (corresponding to each active flow) a packet counter, a byte counter, a token bucket and a contract value. Each flow is assigned one of a plurality of output queues and optionally at least one output threshold value. A token bucket algorithm is employed on each flow to determine whether packets from that flow exceed the contract value. Such packets may be dropped or optimally modified to reflect an alternate output queue and/or alternate threshold before being sent to the selected output queue for transmission from the node. In another aspect an access control list CAM (ACLCAM) contains masked flow information. The ACLCAM provides an index to internal token bucket counters and preconfigured contract values of an aggregate flow table which becomes affected by the packet statistics. In this way flows are aggregated for assignment of output queues and thresholds, possible dropping and possible modification of packets. In another aspect the CAM contains active flow information, the ACLCAM and the aggregate flow table are combined in one system and used to produce in parallel a pair of traffic rate limiting and prioritizing decisions for each packet. The two results are then resolved to yield a single result. [Other References] "Internet Engineering Task Force", Request for Comments 768 User Datagram Protocol, Aug. 1980, pp. 1 to 3. "Internet Engineering Task Force", Request for Comments 791, Internet Protocol DARPA Internet Program Protocol Specification, Sep. 1981, pp. i to 45. "Internet Engineering Task Force", Request for Comments 792, Internet Control Message Protocol DARPA Internet Program Protocol Specification, Sep. 1981, pp. 1 to 21. "Internet Engineering Task Force", Request for Comments 793, Transmission Control Protocol DARPA Internet Program Protocol Specification, Sep. 1981, pp. i to 85. "Internet Engineering Task Force", Request for Comments 1323, TCP Extensions for High Performance, May 1992, pp. 1 to 37. "Internet Engineering Task Force", Request for Comments 2001, TCP Slow Start, Congestion Avoidance, Fast Retransmit, and Fast Recovery Algorithms, Jan. 1997, pp. 1 to 6. "Internet Engineering Task Force", Request for Comments 2005, Applicability Statement for IP Mobility Support, Oct. 1996, pp. 1 to 5. "Internet Engineering Task Force", Request for Comments 2212, Specification of Guaranteed Quality of Service, Sep. 1997, pp. 1 to 20. "Internet Engineering Task Force", Request for Comments 2475, An Architecture for Differentiated Services, Dec. 1998, pp. 1 to 36. "Internet Engineering Task Force", Request for Comments 2581, TCP Congestion Control, Apr. 1999, pp. 1 to 14. "Internet Engineering Task Force", Request for Comments 2582, The New Reno Modification to TCP's Fast Recovery Algorithm, Apr. 1999, pp. 1 to 12. "Internet Engineering Task Force", Request for Comments 2598, An Expedited Forwarding PHB, Jun. 1999, pp. 1 to 11. "Internet Engineering Task Force", Internet Draft, The Rate-Halving Algorithm for TCP Congestion Control, Aug. 1999, pp. 1 to 17. "Internet Engineering Task Force", Internet Draft, Computing TCP's Retransmission Timer, Oct. 1999, pp. 1 to 5. "Internet Engineering Task Force", Internet Draft, Fast-TCP: An enhancement to the current TCP, Nov. 1999, pp. 1 to 9. "Internet Engineering Task Force", Internet Draft, TCP Congestion Window Validation, Dec. 1999, pp. 1 to 11.