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November 30th, 2015 13:00

Datacenter connection via dark fiber

Hello Everyone,

I just want to understand what does it take to connect two datacenters about a couple miles apart using dark fiber. In other words, The brocade DCX SAN switches in each datacenter needs to be connected so that hosts can access storage from either datacenter, so what networking equipment is needed apart from the SAN switches and the dark fiber?. In yet other words, what networking equipment usually exists in between the dark fiber ports of the SAN switches in such datacenters?. Please assist. Thank you. 

2.1K Posts

December 1st, 2015 11:00

I guess the starting point on this question would be to ensure wether you are talking actual dark fiber or an equivalent service from a telcom vendor. If it is a service from a vendor some details on what the service is would be needed to know the best way to connect. If it is real dark fiber then we would need to know the details. depending on just how many miles we are talking about there might be different types of cable deployed (I think... we don't do the dark fiber thing).

If you can get this info it might make it easier for someone to know where to start.

195 Posts

December 2nd, 2015 12:00

I have two buildings that are under 10Km apart, and are connected by two separate runs of private fiber.

My switches have ports with 10K LR SFP optics, and there is nothing but fibre between them.  The light goes in one end, and comes out the other.

5 Practitioner


274.2K Posts

January 7th, 2016 16:00

Hi Zaphod,

        Judging by what you say you have a dedicated fibre pair(s) between these two buildings and as such this fibre is not shared with anything else...correct? These fibres will terminate somewhere in your DC's into patch panels.

    In this case you should be able to connect the DCX ISL ports ( 10K LR SFP) directly to the patch panel using a Single Mode lead...9 Micron . When you use a native dark fibre like that you will have to buy/install the Extended Fabric license, for both of the DCX's, to enable you to increase the Buffer Credits for this 10Km distance.

Hope this helps


195 Posts

January 11th, 2016 12:00

I'm going to give you a yes, and a no.  Yes I believe it is a single-mode fibre connection.  But even without the extended fabrics license the 10km e-port gets 46 buffer credits by default when LE mode is specified; and that is sufficient for the 10km @8Gb.

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