Switching network flow control method and device

Abstract

The embodiment of the invention discloses a switching network flow control method which comprises the following steps: receiving switching network data and judging the magnitude relations between the cache occupation of the received data and a lower threshold and between the cache occupation of the received data and an upper threshold by a downlink line card, wherein the upper threshold is greater than the lower threshold; when the cache occupation is greater than the lower threshold, sending a flow control signal to an uplink line card, wherein the flow control signal is used for enabling the uplink line card to reduce the data sending rate; and when the cache occupation is greater than the upper threshold, sending a back pressure signal to a superior exchange chip connected with the downlink line card to enable the superior exchange chip to stop sending data. The embodiment of the invention also provides a corresponding device which comprises line cards and a router. By adopting the technical scheme of the invention, when the cache occupation of the downlink line card exceeds the lower threshold, the data sending rate of the uplink line card is adjusted, and the cache occupation of the downlink line card can be controlled below a certain level as much as possible, thereby avoiding the problems of deadlock and vicious circle caused by that the downlink line card sends the back pressure signal to the superior chip.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a flow control method and device of a switching network. Background technique [0002] The Internet is mainly interconnected by switching nodes and corresponding communication lines, among which the most important switching nodes are routers. Routers are mainly composed of line cards and switching fabrics. According to the direction of data traffic, line cards can be divided into uplink line cards and downlink line cards. The switch fabric is a bridge connecting the data input port and the output port. It provides a data channel for the line card, so that the data packet can be forwarded from the incoming line card to the destination line card. Switch fabrics can be single-stage, back-to-back, and multi-stage. [0003] There are two data exchange methods in the switching network: the data traffic in the uplink line card directly enters the port of the switch structure fo...

AI Technical Summary

Problems solved by technology

If the reordering and reordering of system data cells is completely performed on the downlink line card, that is, only the downlink chip reassembles and reorders the received data cells, and the switching units SE1, SE2, and SE3 are only performing the transmission of data cells, then , the flow control method of step-by-step back pressure will lead to deadlock and vicious circle as described below

[0009] The reason why the downstream chip puts back pressure on the upper chip is because it has accumulated a large number of cells that cannot be successfully packaged and sorted. It is in urgent need of these missing cells, but at this time its back pressure on the upper chip prevents the cells from being processed. Arrival, so it is both waiting for the cell and rejecting the cell, thus creating a deadlock phenomenon

If the downlink line card has a waiting time limit, that is, after waiting for a period of time, it discards the cells that have not been successfully packaged and sorted, then the packet will inevitably be lost after timeout. As a result, a bunch of cells that cannot be successfully packaged and sorted will come down (because some related cells have been discarded by timeout), which leads to a vicious circle

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