Hi, > ################## > Physical connection: # > ################## > We are terminating with this carrier in a FE port but due to the > distance between them and us at the datacenter location, a FDDI > connection was placed in between like: > > [our > router]----[100baseTX]----[IMC**]----//..fiber..//----[IMC**]----[100baseTX]----[switch > integrated in a Cisco 7200 iron]----[Cisco iron itself/router] > > * Attenuation on the FDDI part was 1.2db respectively 1.3db which is not > brilliant, but okay. More importantly it's within the specifications of > the IMC's. > > ** (IMC = MOXA Industrial Media Converter 101 a.k.a. IMC-101 for both > Single- and Multi mode / SC connectors. We even replaced these with MOXA > EDS-208-M-SC (larger model) as well). > I think here you have the Problems. I can't see any FDDI stuff in this drawing so I will assume for the moment that is just a "FDDI" type fiber you are connected to and everything else is Ethernet. The IMC-101 is just a plain media-converter without any Layer-2 capabilities according to http://www.moxa.com/product/IMC-101.htm but they are not completely dumb devices, so one has to be careful with them.
In the connection above there is something very important to know: Autonegotiation activated in any part of the setup is a bit like playing russian roulette. Either the whole chain supports it perfectly or you are f****d. Make sure that you have Autonegotiation off _everywhere_ and everything is set and bolted to Fullduplex otherwise you might get the strangest and hard to trace errors. I helped someone troubleshoot a similar setup at his decix connection a few years ago and they've been swapping media-converters back and forth till we just used a switch as media converter catching the FDX/HDX issue in the middle so the end's where happy and some people where wondering for a few weeks to who the new mac address (of the switch) belonged which suddenly appeared in the decix mesh till the link got switched over to fiber end to end. I am not of the opinion of the other poster, media-converters are not bad. But the are devices which need to be treated with respect, not everything can be transparently converted to other media. there normally aren't any flp-pulses on fiber since it is FDX by nature, so FDX/HDX negotiation is troublesome. some converters emulate it or catch the autoneg but wether the equipment you connect to the converter is capable of actually talking to it is also not for sure. -sm
