nanog mailing list archives
Re: dark fiber and sfp distance limitations
From: Richard A Steenbergen <ras () e-gerbil net>
Date: Sat, 2 Jan 2010 06:22:03 -0600
On Sat, Jan 02, 2010 at 12:35:15PM +0100, Rene Avi wrote:
With regards to suggested EDFA amplification tricks and similar: If the requirement is not > 150km@1G or 80km@10G/DWDM then I personally strongly disencourage the use of optical amps. 200km / 41dB 1G SFPs are available with costs way below dual EDFAs plus spare, and the chance for the untrained to get eye damages in the process of implementation is far less. So put some laser googles at around 400 USD/each to the purchase list. If one decides to do so then add a post-amplifier on each *end* of the fiber link to increase the signal before hitting the receiver, and do not pump in star-wars class laser power at the beginning ;) .
Depends where you buy your EDFAs, I suspect you could probably get them for less than the cost of a single channel of super long reach optics if you tried hard enough. If you needed to add DWDM later on, and/or dispersion compensation for 10G links the EDFAs will be needed anyways, so sometimes it just makes sense to solve the problem once with an amp rather than trying to solve it on a per-channel basis. You're also vastly exagerating the power of what are effectively metro reach amps, you're really in no danger of making an eye hazard unless you start slapping on ultra long-haul 1500+km transport gear with class 3B lasers (i.e. you're in far more danger from someone with a green laser pointer ordered from the Internet :P). Remember that 1550nm is infrared and very effectively filtered by the human eye, so even a +17dBm output EDFA (the max output for most metro systems) is still going to be class 1M and effectively safe as long as you don't stare at it in a microscope. -- 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)
Current thread:
- Re: dark fiber and sfp distance limitations, (continued)
- Re: dark fiber and sfp distance limitations Mikael Abrahamsson (Jan 02)
- Re: dark fiber and sfp distance limitations Michael K. Smith (Jan 02)
- Re: dark fiber and sfp distance limitations Justin M. Streiner (Jan 02)
- Re: dark fiber and sfp distance limitations Nick Hilliard (Jan 02)
- Re: dark fiber and sfp distance limitations Mikael Abrahamsson (Jan 02)
- Re: dark fiber and sfp distance limitations Richard A Steenbergen (Jan 01)
- Re: dark fiber and sfp distance limitations Alexander Harrowell (Jan 01)
- Re: dark fiber and sfp distance limitations ML (Jan 01)
- Re: dark fiber and sfp distance limitations William Herrin (Jan 01)
- Re: dark fiber and sfp distance limitations Rene Avi (Jan 02)
- Re: dark fiber and sfp distance limitations Richard A Steenbergen (Jan 02)
- Re: dark fiber and sfp distance limitations Rene Avi (Jan 02)
- RE: dark fiber and sfp distance limitations John van Oppen (Jan 06)
- Re: dark fiber and sfp distance limitations Nick Hilliard (Jan 01)
- RE: dark fiber and sfp distance limitations Frank Bulk - iName.com (Jan 04)
- Re: dark fiber and sfp distance limitations Kevin Hodle (Jan 02)
- RE: dark fiber and sfp distance limitations Martin, Paul (Jan 04)
- Re: dark fiber and sfp distance limitations Kevin Hodle (Jan 04)