[j-nsp] GE/10GE link-mode config on M/T-series has no effect

[Richard A Steenbergen]

On Tue, Dec 11, 2007 at 12:16:23PM -0500, Chuck Anderson wrote:
> I don't think so, although what I said may be limited to copper links 
> only:
> 
> http://en.wikipedia.org/wiki/Autonegotiation
> 
> "The debatable portions of the autonegotiation specifications were 
> eliminated by the 1998 release of 802.3. This was later followed by 
> the release of IEEE 802.3ab in 1999. The new standard specified that 
> gigabit Ethernet over copper wiring requires autonegotiation."

What they mean to say is that autonegotiation SUPPORT is mandatory (i.e. 
as a hw manufacturer you must implement it), but it is not mandatory that 
you USE it (it can still be disabled). This is in contrast to FastE 
autonegotiation, which was originally optional and had many problems with 
interoperation between vendors due to an ambiguous specification. With 
10GE, it is actually mandatory that you use it (i.e. as a user there is no 
command to disable it).

You also said that GigE doesn't have a half duplex mode, which is not 
true. Yes it's absurdly rare to find an actual 1GE "hub", but at the time 
the specification was being decided on hubs were still in use and switches 
were still significantly more expensive, so they left it in. 10GE was the 
first Ethernet to actually remove CSMA/CD.

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)