IEEE 40GE & 100GE

Robert E. Seastrom rs at seastrom.com
Wed Dec 12 22:40:16 UTC 2007


"Chris Cole" <chris.cole at 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 at seastrom.com] 
> Sent: Wednesday, December 12, 2007 11:20 AM
> To: Chris Cole
> Cc: Justin M. Streiner; nanog at merit.edu
> Subject: Re: IEEE 40GE & 100GE
>
>
> "Chris Cole" <chris.cole at 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 at seastrom.com] 
>> Sent: Wednesday, December 12, 2007 5:06 AM
>> To: Justin M. Streiner
>> Cc: nanog at merit.edu; Chris Cole
>> Subject: Re: IEEE 40GE & 100GE
>>
>>
>> "Justin M. Streiner" <streiner at 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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