Principles and Practices of Interconnection Networks

CHAPTER 18

Arbitration

While the datapaths of routers are made up of buffers and switches, the control paths

of routers are largely composed of arbiters and allocators.As discussed in Chapter 16,

we use allocators to allocate virtual channels to packets and to allocate switch cycles

to flits. This chapter discusses arbiters, which resolve multiple requests for a single

resource. In addition to being useful in their own right, arbiters form the fundamental

building block for allocators that match multiple requesters with multiple resources.

Allocators are discussed in Chapter 19.

Whenever a resource, such as a buffer, a channel, or a switch port is shared ...