Re: Passive Wave Primer

[Brandon Martin <lists.nanog () monmotha net>]

On 10/13/20 4:01 PM, Mike Hammett wrote:
> It seems incredibly simple to do, depending on the capabilities of your 
> platform.
>
> What am I missing?

If the span between the mux/demux pair is entirely passive, it's fairly 
straightforward.  That's going to limit distances to around 80km or so 
with conventional systems or maybe 120km with systems designed entirely 
around modern coherent optics.

If there are photonic devices in the span, you now have 
customer-supplied light being part of the rainbow that those photonics 
have to handle.  Balancing things at amplifiers requires careful 
coordination with the customer (or adding a separate managed/monitored 
VOA for each alien wave which somewhat defeats the point).  You end up 
with a scenario where a customer can do something screwy and potentially 
affect other waves on potentially multiple spans which your big-name 
carriers are obviously completely freaked out by.

It's obviously possible, but the operational headache seems large enough 
that the major mid-haul and long-haul carriers I've talked to (all North 
America and all midwest, for that matter), don't seem to want to sell it 
despite all the major optical transport platform vendors not just 
supporting it by heavily pushing it.

I really do hope it becomes a real product that I (as a smaller, local 
island operator) can buy, but it just doesn't seem to be there yet at 
least in my region.
--
Brandon Martin