"Chris Cole" <chris.cole@finisar.com> writes:
The 10km reach Transceivers will require no attenuators to operate from 1m to 10km.
Sweet. As an operator, this is exactly what I'm looking for.
The 40km reach Transceivers will probably require attenuators for reaches below 10km, similar to restrictions on 10GBASE-ZR 80km modules today.
That stands to reason...
Also, I have enclosed an article that was published in this month's IEEE Communications Magazine on 100GE Technologies which may give you more details on the types of solutions that will be forthcoming.
Wow, I had no idea that the NANOG mailing list accepted attachments. Someone oughta fix that, heh. Thanks, ---Rob
Chris
-----Original Message----- From: Robert E. Seastrom [mailto:rs@seastrom.com] Sent: Wednesday, December 12, 2007 11:20 AM To: Chris Cole Cc: Justin M. Streiner; nanog@merit.edu Subject: Re: IEEE 40GE & 100GE
"Chris Cole" <chris.cole@finisar.com> writes:
One of the points made by Ted Sealy from Sprint is that they take advantage of the extra link budget in 10GBASE-LR 10km link budget to account for extra connector loss, etc.
Ted Seely and I are of the same mind on this. 2 dB sounds like plenty for connector loss right up until you have to deal with multiple patch bays in a structured system with amateurishly applied mechanical splices. The difference between noting that the loss is a little high but the link still works so you roll with it, and having to spend time on the phone arguing with someone who thinks 24 dB link loss is A-OK, will make the slight additional up front cost for the better grade optics look very inexpensive indeed...
From this discussion it sounds to me like we should stick with 10km initially, and then later come back with an additional specification optimized for low cost, perhaps covering 2km.
I'm on board with that as far as it goes, but has the scenario of adjustable launch powers so that you don't ever need attenuators plus the economy of scale that would come from having *one* type of interface for 1m-10km runs been considered? It seems to me based on what I've seen of the optics market that once you make something a mass-produced commodity the price falls awfully far - suppose the price difference was $250 vs. $375, that's a big difference on a percentage basis but pocket change on an absolute basis.
---rob
Chris
-----Original Message----- From: Robert E. Seastrom [mailto:rs@seastrom.com] Sent: Wednesday, December 12, 2007 5:06 AM To: Justin M. Streiner Cc: nanog@merit.edu; Chris Cole Subject: Re: IEEE 40GE & 100GE
"Justin M. Streiner" <streiner@cluebyfour.org> writes:
I haven't read the draft spec yet to see what's being proposed for a link budget at 3/4/10km, but that's just as important as the physical distance.
That's a really good point, and one which I didn't originally consider pre-coffee. :-)
Link budget information on page 4, here: http://www.ieee802.org/3/hssg/public/reach/Matsumoto_r1_1207.pdf Relative cost estimates on page 5.
Suppositions for ingredients to link budget are here:
http://grouper.ieee.org/groups/802/3/hssg/public/nov07/cole_01_1107.pdf
(page 3)
I'm kind of looking longingly at that extra 3dB, given the slight marginal extra cost and my knowledge of the trained chimp quality mechanical splices that are rife in certain <cough> data centers.
---Rob
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Robert E. Seastrom