Routed optical networks

Fri May 5 04:54:59 UTC 2023

On 5/4/23 19:32, Phil Bedard wrote:

> It’s my personal opinion we aren’t to the days yet of where we can 
> simply build an all packet network with no photonic switching that 
> carries all services, but eventually (random # of years) it gets there 
> for many networks.  There are also always going to be high performance 
> applications for transponders where pluggable optics aren’t a good fit.
>

I think every time the IP space gets close to running an all-packet 
network, the Transport folk come out with an easier way to do it, that 
it's too hard to ignore.

Based on that, I think they will always be one step ahead, with the key 
advantage being reliability of capacity over the distance, for the cost.

The farther your fibre has to run, the costlier it gets to do it without 
DWDM.

I mean, it's only now that 100G-ZR is becoming a reality for packet 
networks, and we are talking thousands of US$ for optics to get us 80km 
- 120km distance. Meanwhile, DWDM vendors can get you 800Gbps per 
wavelength in the same distance (or 30X that distance) far less cheaply.

I get the appeal of not needing DWDM gear to underlay your packet 
network... it's neater and offers fewer points of failure. But unless 
you are dealing with very short distances and can ride a reasonable 
balance between service features and switching/forwarding capacity in 
your router/switch, it's going to be hard to ignore the DWDM gear if you 
are trying to be a serious operation, at that scale, over a wide area.

Mark.
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