Link-Level Flow Control and Buffering - Microarchitecture of Network-on-Chip Routers - page 23

credits
counter

update

update

ready

valid

A data B C

receiver

sender

#credits 3 2 1 0 0 0 0 0 0 0 0 1

updates -1 -1 -1 +-1 +-1 +-1 +-1 +1 +1

clock cycles 0123456789 0 1

D0 A B C

D1
D2
D3
D4

A B C

A B Q Q

Q

C

A B Q Q C

A B Q Q Q

B

C

D5 A Q C

B D6 A C

Fig. 2.13 An example of data transfers on a link between a sender and a receiver governed by
credit-based flow control. The figure includes the organization of the sender and receiver pair and
the flow of information in time and space

When the receiver stops draining incoming data, 5 words are assembled at its
input queue. If the receiver supported fewer positions some of them would have been
lost and replaced by newly arriving words. As shown by the example of Fig. 2.14 ,in