Flow control using output port buffer allocation

摘要

A system for implementing flow control in an information network such as a local area network (LAN) utilizing a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) as specified by the IEEE standard 802.03. The information network transmits computer information such as computer data between various computer systems coupled to the information network. The information network includes information network switches capable of routing information packets received via its input ports to its output ports. The received packets are held in buffers of the output ports before being transmitted via the output ports. A portion of each output port buffer is allocated to each input port. The information network switch provides a control packet such as a PAUSE frame to an upstream source operably coupled to the input port in response to the level occupancy of the portion of the buffer allocated to the input port exceeding a first level. The PAUSE frame inhibits the upstream source from transmitting information packets to the input port. In one system, each up stream source has the capability of ignoring the control packet when the level of occupancy of an output buffer of the upstream source exceeds a threshold level.