Principles and Practices of Interconnection Networks

CHAPTER 13

Buffered Flow Control

Adding buffers to our networks results in significantly more efficient flow control.

This is because a buffer decouples the allocation of adjacent channels. Without a

buffer, the two channels must be allocated to a packet (or flit) during consecutive

cycles, or the packet must be dropped or misrouted. There is nowhere else for the

packet to go. Adding a buffer gives us a place to store the packet (or flit) while waiting

for the second channel, allowing the allocation of the second channel to be delayed

without complications.

Once we add buffers to an interconnection network,our flow control mechanism

must allocate buffers