[c-nsp] QSFP to SFP+ over 300 meters: Can it be done out of box?

[Mikael Abrahamsson]

On Fri, 21 Jun 2013, Troy Lucero wrote:

> Seems there is no option here.  The QSFP-40G/E-LR4 doesn't have an MPO 
> connector like its' SR4 counterpart, so there is no MPO break-away 
> option to choose from if I want to go 10gig over singlemode.

Correct, LR4 is 4 10G CWDM waves over a single fiber pair instead of 4 
parallell fibers like SR4.

> I can't be the only person who has tried this?  Seems like a flaw in the 
> standard to not allow you to connect 10gig beyond 300 meters right out 
> of the box for devices that have QSFP ports.

The people who wanted 40GE were datacenter and server guys. Most higher 
end datacom people only wanted 100GE. The number of variants wanted to be 
kept down. If you want 10GE-LR then you have to get dedicated ports for 
that or go 100GE (which I presume you'll consider budget suicide as well). 
100GE does have a 10x10GE-LR breakout option (however, this is not an IEEE 
standard as far as I can tell).

There is nothing fundamentally stopping for instance Cisco to produce a 
proprietary 4x10GE LR QSFP+, but I guess they didn't feel it made a lot of 
sense.

<http://www.finisar.com/sites/default/files/pdf/Pluggable%20Transceiver%20Challenges-ECOC2012-ChrisCole.pdf> 
might be interesting to read if you want to see where things are and where 
they're headed for the future.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se