Even though it's bad form to reply to yourself, I am doing so, since I
realized my "brain cramp" along the use of a single strand producing half
duplex capabilities. You would still require the dual fiber pair cross
over. The limits of 100FX at half duplex is 412meters, but this is
relevant for fiber connections to a repeater. This was not your case.
The simpler answer to your simpler question is that the fiber interface is
expecting to see both paths partner transmit beam to keep the link status
active. So, if either side of the TX-RX pairs are not functioning, the
whole link is down.
Sorry for the confusion, and the dual reply!
Logical Solutions for Integration
Clarity in an Unclear World
> Well, it seems like an ethernet question to me, so I'll hazard a thought
> two from what you've indicated.
> If an otherwise working full duplex 100FX link has one of its pairs
> then it doesn't automatically try to arrange itself for half-duplex mode.
> In this mode, it would still be bi directional, even over one fiber
> At 100FX, the half duplex length limit is decreased from the max of 2Km to
> 412meters. This may not allow the half duplex mode to be established if
> your length is over 412 meters. In any case, you can't establish "one
> way" traffic, even though you would be able to establish "two way"
> with collisions on one fiber strand.
> Is this an academic situational question or are you interested in
> troubleshooting a real connection?
> George Johnston
> Logical Solutions for Integration
> Clarity in an Unclear World
> > This is not an Ethernet question, but a protocol stack question. I'll
> > give the answer, but a clue would be to look at how stacks like TCP/IP
> > acknowledgements.
> > FR
> > --
> > There is nothing more frightening than ignorance in action. - Goethe
> > > Hello -
> > > I have two 100B-Fx ports(Port1 and Port 2)connected . If I pull out
> > > the Receive on port1, , there is packet loss(as expected).What I want
> > > to know is that why is there no one-way data traffic ( i.e from Port
> > > 1 Tx to Port 2 Rx)?
> > > Any explanation on this would be appreciated.
> > > thanks
> > > kott