System and method for controlling the multicast traffic of a data packet switch

Abstract

A data switch is provided which routes fixed-size data packets from input ports to output ports, using shared memory which holds a copy of each packet in buffers. Output ports have a queue which contains pointers to buffers holding packets bound for that port. The number of shared memory buffers holding packets is compared to the number of buffer pointers in the output queues. In this way, a Multicast Index (MCI), a metric of the level of multicast traffic, is derived. The switch includes a Switch Core Adaptation Layer (SCAL) which has a multicast input queue. Because traffic is handled based on priority class P, a multicast threshold MCT(P), associated with the multicast input queue, is established per priority. While receiving traffic, the MCI is updated and, for each priority class in each SCAL, the MCI is compared to the MCT(P) to determine whether corresponding multicast traffic must be held.

Description

technical field [0001] The present invention relates broadly to communication networks. More particularly, the present invention relates to systems and methods for controlling multicast and broadcast transmissions of packet switches used at switching nodes of a data network. It is an object of the invention to prevent confusion for various types of transmissions when overly high levels of multicast and broadcast transmissions are authorized. Background technique [0002] Over the past few years, the continuously increasing demand for communication network bandwidth has accelerated the development of fiber optic communication lines. Meanwhile, in order to better exploit the huge bandwidth capacity inherent in optical fiber communication lines, it can be observed that WDM (Wavelength Division Multiplexing) technology has been widely used. As a result, transferring more and more data in large communication networks is no longer the bottleneck that used to be at the links rath...

AI Technical Summary

Problems solved by technology

Therefore, although it has been proved feasible to use switches, especially fixed-length packet switches to realize gigabyte switching functions, and the shared media solutions based on rings or buses cannot cope with the huge bandwidth requirements accompanying the implementation of optical fibers, but The price is that it is necessary to use devices whose structure is not well adapted to these mandatory operations and often quickly lead to transmission blocking (which is a very serious problem) without reasonable control. Mechanisms of broadcasting and multicasting

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