Single Mode SFP Question

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Sep 28th, 2009
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Have the need to support a connection between two catalyst 3750 switches.

Problem is I have a single fiber strand of single mode fiber that is between 20 and 30 km in length.

The GLC-BXD/U SFP's will work in the 10km range. Can anyone suggest something else?


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RICHARD MESSINGER Mon, 09/28/2009 - 12:47
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Craig, That would be the right answer if I had a pair of single-mode fibers.

But I only have a single fiber strain to work with being provided by the service provider.

xcz504d1114 Mon, 09/28/2009 - 14:02
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You're right, I completely looked over the "single strand". I don't know of any Cisco product for the 3750 that supports that kind of distance.

There is a Cisco owned company called Scientific Atlanta that Cisco purchased a few years back. At one point they made a media converter that supported single strand up to 40km.

A quick glance, and all I saw were modules for a chassis, no stand alone products.

Here is one of the data sheets from Cisco:

I believe this is the chassis for them:

I dealt with these types of chassis a few years back (different brand), I don't remember the pieces being terribly expensive.



tprendergast Mon, 09/28/2009 - 13:51
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Cisco doesn't have a supported long-range single-strand single-mode fiber transceiver (SFP). You can call TAC and see if they can give you any ideas, but I don't think there will be anything.

Is the fiber continuous? Perhaps you can lease an interface midway from the ISP to bridge the gap. Theoretically, the fiber wave should be able to go the whole distance, but they put those distance limitations on there for a variety of reasons. :)

Wish I had better news for you.

Rate if you found this helpful.

viyuan700 Tue, 09/29/2009 - 06:11
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As suggested by Criag, you can check media converter.

One more solution you can have is CWDM.

I dont know your budget but you can use third party CWDM box like this. I this you will buy CWDM transmitter from Cisco but will use this passive device like shown in tis box. I saw the optical power for CWDM transmitter is 29dB from Cisco have enough power to go 30Km you are looking at (though can go much more than that).

Same solution is available from Cisco also see this link

So you need to buy 2 of such devices and CWDM SFP for your 3750.


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