Hi Lincoln, If i remember right, there are some SFPs that use a single fiber for both tx/rx.
Does UDLD help in such cases? Is there a possibility for a problem in only one direction? -- Tassos Lincoln Dale (ltd) wrote on 12/10/2007 5:39 πμ: >>> Will auto-neg signal one-way fiber failures (after the link has already >>> been brought up and autoneg'ed successfully)? Never tried that. >> Yes, it works much better (and faster) than UDLD. The endpoint which >> has lost receive fiber will immediately signal "RemoteFault" to the >> other end and line protocol will go down on both sides within miliseconds. > > the primary intent of UDLD is detection of mis-cabling at layer-2. > e.g. lets say you had three devices, cabled with tx/rx in a triangle. > > the link may well come up at layer-1 but it sure will do bad bad things at > layer-2 particularly with protocols like spanning-tree! > > UDLD will detect that, autoneg won't. > > the recommendation would be to use both autoneg (layer-1) and UDLD (layer-2). > > > cheers, > > lincoln. > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
