100 KM length LAN connection

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Sep 29th, 2009
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I have one small location 20 users are there the long of the location is 70 to 100 KM.I have cisco 6500 core switch I want to put 3750 access switch to the remote location.Please advice me what Gbic shoul I use ? will it support 6500 SFP 24 port module and 3750 SW ?

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paolo bevilacqua Tue, 09/29/2009 - 01:41
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You need to ask telco, since likely it is not you laying down fiber for 100 Km.

paolo bevilacqua Tue, 09/29/2009 - 03:22
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No, you need to ask telco which fiber type and span length your optics will face.

You do not have a 100 Km span of your own fiber, even if you think so.

Joseph W. Doherty Tue, 09/29/2009 - 04:35
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As described, believe you'll want a "1000BASE-ZX SFP for Long-Reach Single-Mode Fibers" (see more info here: http://www.cisco.com/en/US/prod/collateral/modules/ps5455/ps6577/product_data_sheet0900aecd8033f885.html). NB: it's rated for up to about 70 KM, so 100 KM could be a problem. I also haven't fully confirmed this SFP is supported on both your 6500 line card and the 3750, but from looking at http://www.cisco.com/en/US/docs/interfaces_modules/transceiver_modules/compatibility/matrix/OL_6981.html, it may be.

viyuan700 Tue, 09/29/2009 - 05:36
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Hi Shahul,

Do you have dark fiber between 2 locations which are 70Km to 100Km away?

If yes then you can check the GBIC detail given by Joseph, but lot will depend on the link loss of the dark fiber.

1000BASE-ZX gives you 23 to 28dBm of optical power (its a range in case you are lucky and you get transmitter with 28dBm power). IF there are not too many patching in between you can get more than 70Km but that distance comes with so many IF. See the link loss detail before taking any decision.

If you are getting a link from telco then just see how far is the telco location from both office then you can decide which GBIC is suitable.


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