[c-nsp] What happens during the "shutdown" and "no shutdown" to a 1000BASE-LX10 port

[Peter Rathlev]

On Thu, 2011-08-11 at 00:56 +0300, Martin T wrote:
> Gi0/24   -> Brocade  connected   trunk    a-full a-1000 1000BaseLX SFP

When it says "connected" it's not error-disabling as others have tried
pointing out.

> I'm just curious, what might happened and how did the "shutdown"/"no
> shutdown" improve the situation? Or is it impossible to analyse such
> problems(afterwards)?

I'm not sure how Brocade does, but if it was a Cisco switch in the other
end it could be that e.g. STP loop guard had blocked the link. A link
down/up event would make STP recalculate and thus open the link again.

Another possibility might be a unidirectional link, though I can't see
how forcing down/up would resolve that.

I think the problem is easiest to determine with access to the Brocade
switch. Do the people managing that switch not have logs of some kind to
consult?

-- 
Peter