
10.10 Concluding Remarks 827
can be up to 25 m, and 23 phits can be in transit simultaneously The encoding
allows control flow, framing symbols, and "gap" (or idle) symbols to be interleaved
with data symbols. Symbols are constantly transmitted between switches across the
links so that the switch can determine which of its ports are connected. A packet is
simply a sequence of routing bytes followed by a sequence of payload bytes and a
CRC byte. The end of a packet is delimited by the presence of a gap symbol The
start of a packet is indicated by the presence of a nongap symbol.
The operation of the switch is extremely simple: it removes th