Routed optical networks

Wed May 3 04:29:27 UTC 2023

On 5/2/23 21:32, Jared Mauch wrote:

> I’ve seen proposals for an LSR MPLS/ROADAM type solution, where imagine you are at a hop where in a long distance system solution, you would end up with OEO, but instead you get directionality capability with an IP/MPLS capable device.

My memory is rather fuzzy, but didn't Juniper attempt something like 
this in their PTX's after they picked up BTI? I think the plan was to 
co-locate the ROADM at the bottom of the PTX chassis, or something along 
those lines.

I know Cisco (and Juniper) tried by integrating GMPLS into their code as 
a starting point, but that didn't go very far with customers. It just 
seemed impossible for the Transport teams to allow the IP/MPLS teams 
that level of access into their line system :-).

>    As mentioned previously, the 400-ZR/ZR+/ZR-Bright/+0 optics are the latest example of that.

A rather high barrier to entry for most operators, but we have to start 
from somewhere.

> I know of a few companies that have looked at solutions like this, and can expect there to be some interesting solutions that would appear as a result.  Optical line systems tend to have pretty low power requirements compared to a router, but some of the routers are getting pretty low power as well when it comes to the power OPEX/bit, and if you have the ability to deliver services as an integrated packet optical you could see reduced costs and simplified components/sparing.

The main problem is distance.

If you need to move that kind of capacity more than 50km, it's hard to 
avoid DWDM.

> I’ll also say that I’ve not yet seen the price compression that I had expected in the space yet, but I figure that’s coming.  We are seeing the bits/watt ratio improve though, so for the same or less power consumption you get more bits.  Some of this technology stuff is truly magical.

I think for long spans, DWDM will not only be cheaper, but the only 
feasible solution.

For the metro, it will come down to what motivates the business... 
plenty of features, or plenty of speed.

Also, DWDM vendors are adding speed and distance faster and cheaper than 
the IP/MPLS vendors can. So they will always be one step ahead in that 
respect; and we have the submarine cable systems to thank for that.

Mark.