Abstract: An apparatus and method for traffic shaping in a network switch, which provides for per-connection shaping. A Cell Descriptor (CD)-processing block and a ShapeID processing block operate to de-couple the management of the CDs from the scheduling of the CD output times. The CD-processing block outputs a token (ShapeID) to the ShapeID block. If the token is conforming, it is immediately passed back to the CD-processing block, otherwise it is processed. When the token is “mature” the token is passed back to the CD-processing block. Use of “now” and “later” lists with per-connection ShapeIDs provides priority within a virtual connection (VC) and a virtual path (VP), respectively. This effectively preserves the relative priority for connections being shaped within a VP. Also, the use of a Calendar Queue reduces the complexity of a “virtual finishing time” (VFT) calculation.

Abstract: The present invention is a shared buffer architecture that dynamically allocates buffer size to each of multiple sources depending on buffer pool utilization, estimated per-connection offered load, and the total number of connection established within a given class of service. When the buffer pool is almost empty, each source is allocated a large buffer space, proportional to its estimated offered load. When the buffer pool is more full each source is allocated a reduced buffer space, while maintaining the proportional weighting relationship. The invention keeps track of the amount of input per source and dynamically allocates a proportionate amount of buffer space in the buffer memory for that source. The dynamic allocation is made as a function of the fullness of the memory allocation for all sources. Additionally, thresholds are modulated dynamically as the number of established connections within a given class modulates, providing a predictive aspect to the system, with respect to congestion control.