FC extension question, CWDM

[kbyrd]

I need to connect two MDS SANs switches over dark fiber at a distance of approximately 15 miles (25km). The Long Reach SFPs are rated to 10km. Would I be able to use the CWDM-MUX8A to extend this distance? I'm thinking the answer is no since it is a passive box. Is the ONS15454 my only solution from the Cisco portfolio?

[Tom Randstrom]

If the MDS switch you have is compatible with a CWDM GBIC (DS-CWDM-xxxx=), then you can use these. These will definitely reach 25km. Are you trying to use only a single dark fiber to bi-directional transmission?

[kbyrd]

I'll have to check compatibility. This is fiber channel, not Gigabit. I have plenty of dark fiber and had anticipated using a pair of fibers for TX/RX.

[Tom Randstrom · Accepted solution]

If you have plenty of dark fiber, then no reason to use the CWDM muxes on the end. You can connect directly to the dark fibers.

The CWDM SFPs (DS-CWDM-xxxx) support Gigabit Ethernet and 1-Gbps/2-Gbps Fibre Channel.

MDS compatibility matrix:

http://www.cisco.com/en/US/docs/storage/san_switches/mds9000/compatibility/matrix/hwcompat.htm

[kbyrd]

Thanks for the reply, baileyshbr. You anticipated my question as to whether or not I needed the Mux. The customer wants 4gig, so I think I'll propose port channeling two of the 2gb ports. I'm sorry for the elementary question, but for port channleing two ports (2 pairs of SM dark fiber), I would use, for example, a pair of DS-CWDM-1470s and a pair of DS-CWDM-1490s? Actually, I guess I could use all DS-CWDM-1470s and have a spare on the shelf.

Am I also correct in assuming that whether or not I use the CWDM MUX will not affect the distance? Meaning I can go up to 60km between my MDS on dark fiber with the DS-CWDM-xxxx?

Thanks again, baileyshbr.

[Tom Randstrom · Accepted solution]

My calculations indicate that you could go at least 60km using the CWDM MUX and longer without the MUX.

I've attached a diagram to try to explain your configuration options (a picture is worth a 1,000 words).

Also, below is a link for the Cisco CWDM MUX devices with more deployment options (for future expansion options).

<http://www.cisco.com/en/US/prod/collateral/modules/ps5455/ps6575/product_data_sheet0900aecd8029d01b.html>

I hope this helps.

Tom

[kbyrd]

Excellent. That's just what we needed. We can't tell from the compatibility tables if the MDS 9124 is compatible with the DS-CWDM-xxxx. Do you know?

Thanks again for the PPT and the great information, baileyshbr.

[Tom Randstrom]

I am do not know the MDS product.

Is there a way to run an inventory to find out which model number switch fabric is installed? You might try to post a question on the Data Center connection to find out how you determine which fabric you have and if it is compatible.

Tom