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Distances for singlemode fiber optic cable...

Does the singlemode fiber work for distances less than 500 mts using 1000BaseLX/LH GBICS...?....I am not sure if I can only use this kind of fiber for distances greater than 550 mts....

5 REPLIES
New Member

Re: Distances for singlemode fiber optic cable...

This command should give the IP address for a given MAC adddress

sh ip arp H.H.H

Of course, tools will automate the process and save you a lot of time.

New Member

Re: Distances for singlemode fiber optic cable...

I've mostly heard that single mode fiber is used for longer distances ( a few KMs ) where as multimode is used for shorter distances. Not sure though.

Fareed

New Member

Re: Distances for singlemode fiber optic cable...

I feel that distance limitations for any media are meant to be the MAXIMUM, unless there is a specific reference to minimum distances. SM fibre should work at the distances you have mentioned, and can go upto the rated distances.

Cisco Employee

Re: Distances for singlemode fiber optic cable...

The following link gives the distance specifications used by SMF and MMF in GBICs

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/cnfg_nts/ethernet/5399_01.htm#xtocid7

Usually, SMF is used for longer distances where as MMF is used for shorter distances. Ultimately it depends on the light source used to carry the data. SFM usually usef laser and MMF uses LED light source.

New Member

Re: Distances for singlemode fiber optic cable...

The link sshant has provided is an excellent reference for your question.

Note that further up in that same document, it states that for the WS-G5487 1000BASE-ZX GBIC, you would need an optical attenuator for short distances. ("Short" in this case means less than 25 kilometers! The ZX is designed for *long* hauls.)

There is no such concern noted for the WS-G5486 1000BASE-LX/LH GBIC, so you should be fine.

However, if you're using multimode fiber optic cable with your GBIC, read the note about mode-conditioning patch cords.

In fact, read the whole thing. It's a pretty comprehensive treatment. (OK, you can probably skip at least most of the "Translated Safety Warnings".)

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