newbery@rata.vuw.ac.nz (Michael Newbery) (12/11/90)
I have a short (150m or so) length of 62.5u fibre with a cisco AGS and a Cabletron FOT-1 (F.O. transceiver using FOIRL standard, SMA connectors) on one end and a Cabletron FR3000 repeater (Fibre optic SMA & AUI repeater) on the other. It doesn't work. The LINK light is on on the FOT-1 but not on the FR3000. Transmissions from the cisco light the RECEIVED and (~75%) JAM lights on the FR3000 (but NOT the COLLISION light!). This is not a situation that is described in the FR3000 or FOT-1 manuals. Pings from the cisco to the connected network fail. Pings to the cisco interface connected to the FOT-1 fail. Replacing the FR3000 with a MR2000 (AUI & thinwire repeater) + another FOT-1 lights the link light on the new FOT-1 but transmissions from the cisco still light the RECEIVED and JAM lights (only) on the MR2000! Again, not a situation described by the MR2000 manual. This setup actually allows the odd ping through but the line is still unusable. We moved the FR3000 next to the cisco, connected only via FO patch leads and the LINK light stayed off and the JAM light went on with most transmissions from the cisco. The LINK light on the FR3000 seems to be 'alive', it flashes briefly when you power cycle the FR3000. Putting the FOT-1 and the FR3000 on a bench and connecting them with a piece of F.O patch cable seems to work EXCEPT that the LINK light does not come on, but transmissions transit the repeater (at least, I can LanLoad a TRW ACU through it in either direction) without rasing JAM. The fibre installer claims the fibre is good and the OTDR runs seem to back this up. However, the fibre run is actually FR3000[SMA----ST barrel ST--------ST barrel ST-------ST barrel ST---SMA]FOT-1 I.e. two lengths of ST terminated fibre patched together in the middle through barrel connectors with SMA-ST patch leads at either end. We don't have an OTDR trace on the whole run, just the individual sections. We have swapped patch leads, barrel connectors and FOT-1s just in case one of them was faulty, to no avail. We have carefully cleaned the ends of the patch leads with isopropyl alcohol. What do we do now? Where do we look? Does anyone know what the lights on the Cabletrons are saying to us? Alas we DON'T have an OTDR or even a Lanalyzer. Help! Oh yes,... this segment of the network services the Vice-Chancellor's (University talk for C.E.O) office. Sigh. -- Michael Newbery<newbery@rata.vuw.ac.nz> Cheop's Law: Nothing ever gets built on time or within budget.
haas%basset.utah.edu@cs.utah.edu (Walt Haas) (12/11/90)
In article <1990Dec11.042930.23031@comp.vuw.ac.nz> newbery@rata.vuw.ac.nz (Michael Newbery) writes: >I have a short (150m or so) length of 62.5u fibre with a cisco AGS and a >Cabletron FOT-1 (F.O. transceiver using FOIRL standard, SMA connectors) on >one end and a Cabletron FR3000 repeater (Fibre optic SMA & AUI repeater) >on the other. >It doesn't work. [sad story deleted] We use this setup a lot, it works fine for us. Make sure that the SQE on the fiber transceivers is turned off. Use the lower power level. Build a dummy network at the repeater end to make sure you aren't seeing a problem from the remote Ethernet passing through the fiber link. Beg, borrow or steal an OTDR long enough to make sure that the whole fiber path works correctly, you could have a bad ST barrel. Make sure there are no grouding problems at the remote end. -- Walt
newbery@rata.vuw.ac.nz (Michael Newbery) (12/12/90)
In article <1990Dec11.080739.4351@hellgate.utah.edu> haas%basset.utah.edu@cs.utah.edu (Walt Haas) writes: >In article <1990Dec11.042930.23031@comp.vuw.ac.nz> newbery@rata.vuw.ac.nz (Michael Newbery) writes: >>I have a short (150m or so) length of 62.5u fibre with a cisco AGS and a >>Cabletron FOT-1 (F.O. transceiver using FOIRL standard, SMA connectors) on >>one end and a Cabletron FR3000 repeater (Fibre optic SMA & AUI repeater) >>on the other. >>It doesn't work. [sad story deleted] > >We use this setup a lot, it works fine for us. Make sure that the SQE on It works fine for us too on the other 20 or so segments. >the fiber transceivers is turned off. Use the lower power level. Build Yes. Yes (tried both). >a dummy network at the repeater end to make sure you aren't seeing a >problem from the remote Ethernet passing through the fiber link. Beg, borrow Same symptoms regardless of whether remote thinwire connected or not. >or steal an OTDR long enough to make sure that the whole fiber path works >correctly, you could have a bad ST barrel. Make sure there are no grouding We tried swapping barrels & rotating though our stock of barrels---no change. >problems at the remote end. Thanks, I'll try this one (and I thought I'd managed to put earthing problems behind me when we went to fibre :-|) >-- Walt Thanks for the response. -- Michael Newbery<newbery@rata.vuw.ac.nz> She learnt to stab her food with a silver fork. "Pavanne", Richard Thompson.
newbery@rata.vuw.ac.nz (Michael Newbery) (12/12/90)
I've found and fixed the problem----it was a faulty transceiver cable between the cisco and the FOT-1. Mumble. I was looking for the fault at the wrong end of the link. -- Michael Newbery<newbery@rata.vuw.ac.nz> Aequam memento rebus in arduis servare mentem Horace Od. II iii 1