Arrangement for minimizing data overflow by managing data buffer occupancy, especially suitable for fibre channel environments

Abstract

A method manages a communications link in which a first device () interfaces with a first channel extender () and in which a second device () interfaces with a second channel extender (), and in which the first and second channel extenders () communicate with each other through a communications medium (). The method involves (FIG.A) monitoring an occupancy ('b') of a receive buffer () in the first channel extender () during transmission from the second channel extender () at a first transmission rate (R); (FIG.B) at a first time (T) when the occupancy of the receive buffer () exceeds a first threshold (B+B), immediately instructing () the second channel extender () to cease transmission to the first channel extender (); (FIG.C,) monitoring for an overflow condition in the receive buffer (); if (FIG.D,) the overflow condition is present, specifying () that a future transmission to the first channel extender () be at a second transmission rate (R') that is lower than the first transmission rate (R); and instructing (FIG.D,) the second channel extender () to resume transmission to the first channel extender ().