
Flow
control
Input port
FIFO
CRC f
check
1 Route
control
Flow
control
Input port
Π
FIFO
+
! CRC 1
check
1 Route
control
64
Central
queue
In
arb
Out
arb
RAM
64x128
8x8
Crossbar
64
Output port
FIFO
Flow
control
XBar
arb
&^
CRC
gen
Output port
yH FIFO
8
Flow
control
XBar
arb
Dhrt
CRC
gen
FIGURE 1038 IBM SP (Vulcan) switch design. The IBM SP switch uses a crossbar for unbuffered packets
passed directly from input port to output port, but all buffered packets are shunted into a common memory
pool.
Arbitration logic schedules flits into and out of the central queue RAM.