single mode fiber and switching issues

[N11]

Hopefully I can get some help on this one...

There are two portions to this network I'll refer to as segment A and segment B.

Segment A is currently online and working.

Basic diagram:
Router --> 24 port catalyst --> 10GBIC catalyst ---------(multimode spanning to 10 different locations) ---> 24 port/2GBIC catalyst (10 locations)

So that is segment A and it is running fine right now.

Segment B is being designed to connect right to the 24 port catalyst behind the router, and branch off as:
8GBIC catalyst 3508 -------------------(single mode spanning to 6 different locations) ---> 24 port/2GBIC DELL Powerconnect 3024 (6 locations)



The problem is that the 3508 for segment B doesn't have any rj45s, so there is no way to connect it to the primary switch. To resolve this I've grabbed a couple of these:
http://www.alliedtelesyn.com/allied/products/viewproduct.asp?category=3&id=94

However, they do not appear to actually work. I'm trying to couple one of these with each Powerconnect 3024 in segment B, but get no link lights whatsoever. The fiber and connectors test fine....

so I prepared a basic test. I took 2 of the Dell switches and 2 of these media converters. One converter plugged into an rj45 on one switch, the other to an rj45 on the other switch. Then a single mode cable to connect to the two media converters. No link light. The 10/100 ports light up fine in 100 full duplex... yet the fiber ports are seeing no activity.

Perhaps the easiest solution is to just forget the media converters and Dell switches and just go Cisco with Cisco modules but that is a highly expensive route that I don't want to try until all hope is lost with this media conversion.

Any help or insight would be appreciated.

 

[ScottMac]

Well, hmmm.

I guess, start with the basic stuff:

Shine a flashlight into the fiber at one end, have someone looking for the light at the other end...make sure the fiber is intact. If you know someone with an OTDR or Optical Power Meter, have them scope the fiber. Single mode has to have a quality termination; the actual fiber is so thin (8.3 microns) that poor termination can cause a major misalignment or over-attenuate the signal.

If you haven't already tried, swap the TX/RX pair on one side.

Check your GBICs to make sure they're the right type. (what Cisco part number are they?)

Check the config on the converter box to make sure it's set up for single mode.

If the box can be reconfig'd for multi-mode easily, connect a short MM jumper between the converters.

What kind of distance are these fibers spanning?


Check 'em out & let us know.

Scott

 

[drquest]

First I'd check a few simple things...

Make sure your fiber connectors are clean

Make sure you have the near end transmitter (TX) connected to the far end (RX) and vise versa. That's a thing that can be easy to overlook.

You didn't mention the distance, and I couldn't find anything in their specs to back it up, but it sounds like you are testing this within the same building, or at least fairly close. These will have operating distance limitations, which with single mode fiber can be miles, but they also don't like to operate at too close of distances either. You might have to get some fiber pads, to pad down the power so they can operate closer together. Again I couldn't find that specific thing in their documents, but I have seen it happen before.

I personally like the products this company makes: Radiant Their 221 model only needs 1 fiber to provide up to 100base full duplex... works real nice...

mrpeabody

 

[me19562]

I think ur problem is that u r trying to connect a 100Mbit link fron de Dell switch to a Gigabit link in the 3508 Catalyst and as far i know the GBIC don't support
autonegotation. The GBIC have to connect at GBIC, though so.



Good Luck

 

[N11]

I appreciate the feedback.

My first thought was either bad termination or something resulting from the fusing that was done... all six remote points spanning anywhere from 800-1200 feet were fused together with the main location at a single point... but when I put the switches right next to each other with a fiber jumper and still had nothing with either the media converters in the dells, or the cisco modules and the dells over a 2 meter piece of brand new fiber w/SCs I knew something wasn't right.

and the fiber had tested good on multiple occasions. The fiber modules I was using after giving up on the media converters are Cisco 5486's.


I did get it working this past afternoon. I had a cisco 3512 (12-10/100s, 2gbics) shipped in with a 3550 (2 -10/100/1000s 10gbics). Put the 3550 at the primary point of segment B and the 3512 in one of the remote buildings with a 5486 module in each. -- this worked fine. A lot more expensive but it is functional.


Should have been 100% Cisco from the beginning. A fine lesson in the cards dealt when cutting price corners.