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 <t...@ninjabadger.net> 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