Giles Coochey wrote:
> On 09/07/2011 01:06, Les Mikesell wrote:
> >Turning off negotiation pretty much guarantees problems if
> >anything changes at the other end or you use an unmanaged switch.
> >And the gigabit spec requires auto-negotiation.
>
> Let me make it clear - auto-negotiation only works if
> auto-negotiation is configured on both sides. It does not work if
> one side hard codes the speed and duplex. Both sides have to be set
> for it to negotiate. Agreeing on speed and duplex ensures that it
> will work.
>
> If something is going to change on the remote end without you
> knowing, or your provider is using an unmanaged switch then it's
> time to change provider :-) - they obviously are cheapskates and
> don't have any change management control on their systems.
>
> Gigabit is different.
My reading of the spec is that when a port is configured for 1GbE
over 1000BASE-T (copper), "disabling" auto-negotiation disables the
advertising of the auto-negotiation for 10BASE-T and 100BASE-T, but
auto-negotiation is still advertised and operational for 1GbE.
Auto-negotiation cannot be disabled for 1000BASE-X (optical fiber).
Deviation from the spec would mean such kit is Ethernet-like.
An ability to "set" auto-negotiation one way in the user interface
while leaving the hardware in a different - standards conforming -
state is possible.
--
Charles Polisher
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