Fibre Cabling Suggestions

[Steven Clementi]

Let me describe the situation:

I have 2 Cisco MDS9124's that I am trying to connect 2 sites with.

Here is the situation:

The fibre between the buildings is said to me "multimode". It is also said to be a straight through patch, no mechanical/digital equipment in between. The distance is about 3000 feet.

The customer already has several other devices connected site to site using these fibre pairs, simply using 62.5/125 multimode patch cables. These are NOT SAN devices though.

When I connect up the MDS's, I do not get any connectivity. Is it simply too far out of range for multimode cables and a SAN environment?

I have long wave sfp's in the switches and they work fine if I directly attach a simple lc-lc patch cable between them. (I have more switches onsite that I tested with).


What would you suggest for a situation like this? Would using single mode cables help in connecting the sites?

Steven

[Uwe Zessin]

3000 feet is, what? more than 900 meters?

A 62.5 micron multimode cable of OM1 quality /(200 MHz/kilometer) is good for 200 meters when using 1 GigaBit/second. I doubt that you will get a working link, even if you use multi-mode SFPs.

Long-wave GBICs/SFPs require a 9 micron (single-mode) cable. They work on multimode cables when the distance is short, but not on _that_ distance.

The customer _does_ need single-mode cables or some kind of IP bridge with a lower bandwidth.

[IBaltay]

Hi,
maybe some useful info could be find in the SAN design guide:
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00403562/c00403562.pdf?jumpid=reg_R1002_USEN

[Uwe Zessin]

maybe? No really ;-)

The SAN Design Guide contains a lot of useful information in one place if you are dealing with different core diameters, mono/multimode, different speeds and so on.

[Steven Clementi]

Thanks. We ended up going with Multimode Extenders between sites. If you need more information about models we used, just ask.

Steven