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Brad, Let me make a few comments. For 802.3bj it is necessary to use Clause 73 for
auto-negotiation because Clause 73 already supports port types for four-lane
twinax and back-plane. If new 100G port types are being added for these media,
they need to be included in Clause 73. Clause 73 also gives you FEC negotiation
for free. Clause 73 clearly does not work over optical media. You can use ordered sets for exchanging ability and
requests, but this only works if both sides of the link are running at the same
speed and the error ratio is not too bad. For next generation optics you are
going to need to decide whether you need to negotiate speed in addition to determining
FEC operation (for example you might want to negotiate between 40GBASE-SR4 and
100GBASE-SR4). If you do decide to negotiate speed you could consider re-using
Clause 37 for auto-negotiation (which operates at a 1.25G data-rate). If you are not negotiating speed but are just
concerned about bit errors, then the task being performed is really link
training rather than ability resolution. Arthur. From: Brad Booth [mailto:Brad_Booth@xxxxxxxx] Stephen, It depends on the FEC
protocol adopted, implementation requirement, and the associated latency. The
discussion got started around the idea of using Clause 73 AN for FEC ability
exchange in the optical domain. Considering we’re still
in the study group phase, some of those questions cannot be answered as we have
not adopted an FEC proposal. If an exchange protocol is required, then IMHO the
use of sequence ordered sets would be preferred over creating of a new autoneg
protocol. Cheers, |