On Mon, Mar 15, 2010 at 10:15:51PM -0400, Jeff Kell wrote:

And a follow-up to my original question...

I'm reading the Cisco SFP GBIC-SH spec for 50u OM3 and it shows a rating of 1000m? Really? That's better than the LH rating over the same fiber (550m)?

Hi Jeff, I don't know of any optics with a 1km reach over MMF at either 1G or 10G rates. Over OM3 fiber you can get ~260-300 meters of 10G, over older MMF you can potentially get much less, it depends on the exact signal you're trying to pass. Yes you can get 550 meters with 1G LX over MMF, but the MMF itself is ultimately what is limiting you. I recently did a NANOG presentation on some of this, you may want to take a look at: http://www.nanog.org/meetings/nanog48/presentations/Sunday/RAS_opticalnet_N4... Personally my take on this particular problem is to stop doing MMF runs and standardize on SMF where possible. If you do any amount of shopping at all you can find optics for SMF which are barely any more expensive than optics for MMF, especially if you're only talking about 1GE or 10G SFP+. The grief caused over the long run by having more installed MMF plant, especially as you try to move to 10G speeds and beyond, is IMHO not worth the relatively small short term cost optimization. -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)