Apparatus and method for traffic shaping in a network switch

摘要

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.