Cheap switch with a couple 100G

Tom Hill tom at
Sun Nov 25 21:40:47 UTC 2018

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.


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