[c-nsp] LX GBIC at half duplex?

[Saku Ytti]

On (2012-10-23 22:06 -0500), Tony Varriale wrote:

> None of GBIC will do half duplex IIRC.  And, they won't do subrate.
> The negotiate is there to appease the other end if it tries.

This is painfully common misconception. So some, even serious SPs tend to
have standard of disabling autonego and forcing links.

Autonego gives other benefits than agreeing on duplex. Like it is used for
RFI (remote fault indication) signalling, which will prevent issues where
one side is up and another side is up.

Also autonego can communicate that remote end was shutdown
administratively, even hardware today supports this, but I've not seen any
vendor implement it in software. I think it would be kinda nice to see in
syslog, if remove has been shutdown operationally or not.

It's shame 802.3 is so very very hard to follow, some professional from
industry who knows the standard and has built devices which interoperate
should do some write up in wikipedia to clear up on what ethernet can do
and specifically why autonego is good.

-- 
  ++ytti