Dark Fiber, Brocade switches, Distance

[Adam Garsha]

I know this is not ideal.

Question:

If you have 2 datacenters with dark fiber between the two sites. These sites are less then "a few blocks" apart (<0.5mi).

Is it possible to connect fiber from a switch at data center "A" to an HBA at data center"B" without having any fabric switches at data center "B"?

i.e. a "really long" fibre connection from fabric at site "A" to a device at site "B"?

What is the longest you can go without having switches at each site? What other questions should I be asking/answering if I don't have the budget to buy additional switches (now), but I want to put one device at a remote location?

[Uwe Zessin · Accepted solution]

As far as I can tell, the longest supported distance between a device and a switch is 500 meters, assuming 1 GigaBit/sec and a multimode fiber with 50 micrometer core.

[Basil Vizgin]

As I know, HP didn't have HBA's with longwave transiever. So you limited to 500 meters.

[Luk Vandenbussche]

Hi,

You can go to 300 m at 2 GBps switch. These days you have yet 4 Gbps switch
You need a switch with longwave SFP at each location if you go over this distance.

[Peter Mattei]

First you need to know what type of fibre you have between the buidings:
9um single mode or
50 um multimode

HBAs and most Arrays only have 50um multimode transceivers. In addition they do not have enough buffers to allow sustained throughput beyond the supported distances.
these are
500m @ 1Gbit
300m @ 2Gbit
150m @ 4Gbit

For more details have a look at the HP SAN design reference guide on
www.hp.com/go/sandesign

Cheers
Peter

[Duncan Edmonstone]

Adam,

Also you need to check what sort of fibre has been installed - as much of this was traditionally installed by our networking colleagues you might find that the fibre is in fact 62.5/125 rather than the higher bandwidth 50/125 fibre commonly used in FC SANs. If the fibre is 62.5/125 then the achievable distances are even shorter:

1Gb -> 200m
2Gb -> 150m
4Gb -> 70m

HTH

Duncan

[Richard Jackson_6]

No.

Luk has the correct answer here.

I suggest you buy some 'cheap' switches that can accept long disance SFP's for your remote site.

Rich

[Jim EVA Hill]

Are you the same Adam formally from Wisconsin?

[Adam Garsha]

Yes, Jim; I am the same Adam. How's it going?

Others, I read up on this stuff now... I appreciate the jump start, it really helped. For future forum searchers, the brocade free 101 course talks all about multi-mode vs. single-mode and fibre types and distances, etc. good stuff.

We have single-mode fibre between the sites and we are going to order some additional switches to allow LWL single-mode ISL's.

Which brings me to my next post...

[Jim EVA Hill]

Things are going well. We are now on the EVA5000 and new Alphas. You should email me so we can keep in touch. I promise I won't ask you any work questions.