Routed optical networks

Tue May 9 06:50:06 UTC 2023

>
> The optical network is made up of the photonic portion and then the
> transponder/muxponder portion.
>
Thank you for that direct definition. I'm serious (not sarcastic).

One thing I've written about in papers is the nomenclature problem, and I'm
in good company.
Bill Norton had written explicitly "the lexicon is important", and dwelt on
that theme, in his book "the internet peering playbook".

This is the source of a lot of grief.

Cheers,

Etienne

On Mon, May 8, 2023 at 9:57 PM Phil Bedard <bedard.phil at gmail.com> wrote:

> I guess let’s not confuse two things.  The optical network is made up of
> the photonic portion and then the transponder/muxponder portion.   A single
> term like “DWDM” can be confusing since it can refer to both.   It will
> take a long time (maybe never) to remove the photonic switching part of the
> network.  However, it’s always been cheap to deploy because optical vendors
> tended to subsidize that network using sales of the other portion, the
> transponders, which you buy more and more over time.  Those photonic
> components are expensive.
>
>
>
> On the DWDM signal portion, I’m not talking about 100ZR compared to 100G
> on a transponder or DWDM line system.  100ZR has had to deal with the power
> limitations of QSFP28 ports, which QDD/OSFP do not suffer from.  There are
> quite a few QDD pluggables in production today capable of supporting 100G
> signals over 1000s of km or 400G near 1500km.  Now that’s not what you can
> get out of some external transponders, so those will still have their place
> in high performance applications.   When you move to 800G, 1.2Tbps single
> channel they also have their own distance limitations.  So it really
> depends on the application and the network.
>
>
>
> Phil
>
>
>
> *From: *NANOG <nanog-bounces+bedard.phil=gmail.com at nanog.org> on behalf
> of Mark Tinka <mark at tinka.africa>
> *Date: *Friday, May 5, 2023 at 12:55 AM
> *To: *nanog at nanog.org <nanog at nanog.org>
> *Subject: *Re: Routed optical networks
>
>
>
> 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.
>

-- 
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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