nanog mailing list archives

Re: Routed optical networks


From: Etienne-Victor Depasquale via NANOG <nanog () nanog org>
Date: Tue, 2 May 2023 23:11:36 +0200


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


Jared, I understand your point in the above statement to be that
directionality is cost-effectively implemented through label-switched
paths,
rather than (ROADM-enabled) optical path switching.

Do I understand right?

Thank you.

Etienne

On Tue, May 2, 2023 at 9:33 PM Jared Mauch <jared () puck nether net> wrote:



On May 2, 2023, at 2:29 PM, Etienne-Victor Depasquale via NANOG <
nanog () nanog org> wrote:

On Mon, May 01, 2023 at 02:56:47PM -0600, Matt Erculiani wrote:
In short, the idea is that optical networks are wasteful and routers
do a
better job making more use of a network's capacity than ROADMs. Take
the
extra router hop (or 3 or 8) versus short-cutting it with an optical
network because the silicon is so low-latency anyway that it hardly
makes a
difference now. Putting more GBs per second on fewer strands means
saving a
lot of money on infrastructure costs.

This is a very convoluted way of backing into the ole packet-switched
vs. circuit switched decision.

I don't follow.
While ROADMs can be thought of as circuit-switchers,
the number of concurrent clients and switching latency put ROADMs on a
different operational level than packet switchers, right?


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

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.

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.

- Jared



-- 
Ing. Etienne-Victor Depasquale
Assistant Lecturer
Department of Communications & Computer Engineering
Faculty of Information & Communication Technology
University of Malta
Web. https://www.um.edu.mt/profile/etiennedepasquale

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