RE: Interface reality check
Dave,
You are right, I forgot that the receive side is more complicated than
the transmit
side.
Just to put some hard numbers, a simple implementation as presented by
Rick in
pg 13:
http://grouper.ieee.org/groups/802/3/ae/public/mar00/walker_1_0300.pdf
will require gates equivalent to about 1400 flops. I believe it can be
optimized
further, but as of now, the intrinsic complexity is about 1100 storage
elements.
I wonder how this compares with the number of gates required to
implement other
aspects of the wan phy - is it too much, comparable or negligible?
Regards,
Birdy
------------------------------------------------------------
Bharadwaj,
The issue with 66-bit alignment vs 8-bit alignment arises at the receive
end.
The SONET section framer provides a byte-aligned output. If the payload
is
byte aligned then the payload delineation mechanism can hunt directly.
If the
payload is 66-bit aligned, then the delineation mechanism must hunt on a
bit
by bit basis. Bit-slipping vs byte-slipping involves more circuitry.
...Dave
David W. Martin
Nortel Networks
+1 613 765-2901
+1 613 763-2388 (fax)
dwmartin@nortelnetworks.com
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