Cheap switch with a couple 100G

Ben Cannon ben at
Sun Nov 25 21:43:17 UTC 2018

At this point, with 400g coherent in production never mind long-haul testing; why bother lighting with anything slower than 100g coherent, especially at essentially the same price.  It just makes no sense.  It got skipped.  We’re better for it IMO.

- Ben Cannon, AS15206

> On Nov 25, 2018, at 1:40 PM, Tom Hill <tom at> wrote:
> On 25/11/2018 21:22, Baldur Norddahl wrote:
>> If it is passive, you could tell them it is for 10G but use it for 25G?
> The mux isn't the problem, it's that there aren't SFP28 optics commonly
> available in C/DWDM wavelengths. Yet. If they were, well maybe...
> ... However, your trouble then is that 25G will have similar loss
> characteristics to 4x25 100GBASE, which to put it simply, isn't as
> favourable as your existing 10G transceivers. You will *really* begin to
> care about how 'direct' your cross-connects are.
> Coherent optical transport has become far more common in recent years
> for the same reasons, and pizza-box solutions for this are even coming
> in whitebox guise now (see Facebook/Cumulus).
> On the retail side, if you're buying 'grey' wavelength services from
> optical network operators as opposed to running your own transport, they
> now tend to be bundling everything into coherent line sides through the
> use of muxponders.  The problem with buying 25G services then becomes
> "our vendor doesn't discount as hard for the 4x25G muxponder part as
> they do for the 10x10G part!", or "we'll have to buy this for you
> especially, and so you're footing >25% of the bill".
> Chicken & egg: someone has to move first... And I don't see the ASR9k
> and Juniper MX BUs rushing to support 25 & 50G.
> -- 
> Tom

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