Principles and Practices of Interconnection Networks

CHAPTER 12

Flow Control Basics

Flow control determines how a network’s resources, such as channel bandwidth,

buffer capacity, and control state, are allocated to packets traversing the network.

A good flow-control method allocates these resources in an efficient manner so the

network achieves a high fraction of its ideal bandwidth and delivers packets with

low, predictable latency.

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A poor flow-control method, on the other hand, wastes

bandwidth by leaving resources idle and doing unproductive work with other re-

sources. This results in a network, like the one we examined in Chapter 2, in which

only a tiny fraction of the ideal bandwidth is realized and ...