[c-nsp] Confirmation of Gigabit Ethernet autonegotiation behavior

[Peter Rathlev]

On Thu, 2013-01-24 at 22:03 -0700, John Neiberger wrote:
> A few of us at work have been discussing autonegotiation in gigabit
> Ethernet networks and I wanted to get a clarification. I know that on Cisco
> devices with Fast Ethernet, if you manually set speed and duplex, this
> disables Nway autonegotiation completely. However, I don't think that is
> the case for gigabit links since the autonegotiation process is so much
> more important. I believe that it still participates in autonegotiation but
> only offers the configured speed and duplex setting in the negotiation
> process.

https://supportforums.cisco.com/thread/146915 asks roughly the same
question. There's no official Cisco reply there, but the poster refers
to the following:

http://standards.ieee.org/reading/ieee/interp/IEEE802.3af-2003interp-6.pdf

So it seems 1000BASE-T cannot work without MASTER/SLAVE selection which
is one part of auto-negotiation. On the other hand 1000BASE-X can work
without auto-negotiation (AFAICT) but if Cisco uses this or not I don't
know.

-- 
Peter