RE: Routed optical networks

[Vasilenko Eduard via NANOG <nanog () nanog org>]

Disclaimer: Metaverse has not changed Metro traffic yet. Then ...

I am puzzled when people talk about 400GE and Tbps in the Mero context.
For historical reasons, Metro is still about 2*2*10GE (one "2" for redundancy, another "2" for capacity) in the 
majority of cases worldwide.
How many BRASes serve more than 40000/1.5=27k users in the busy hour?
It means that 50GE is the best interface now for the majority of cases. 2*50GE=100Gbps is good room for growth.
Of course, exceptions could be. I know BRAS that handles 86k subscribers (do not recommend anybody to push the limits - 
it was so painful).

We have just 2 eyes and look at video content about 22h per week (on average). Our eyes do not permit us to see 
resolution better than particular for chosen distance (4k for typical TV, HD for smartphones, and so on). Color depth 
10bits is enough for the majority, 12bits is sure enough for everybody. 120 frames/sec is enough for everybody. It 
would never change - it is our genetics.
Fortunately for Carriers, the traffic has a limit. You have probably seen that every year traffic growth % is 
decreasing. The Internet is stabilizing and approaching the plateau.
How much growth is still awaiting us? 1.5? 1.4? It needs separate research. The result would be tailored for whom would 
pay for the research.
IMHO: It is not mandatory that 100GE would become massive in the metro. (I know that 100GE is already massive in the DC 
CLOS)

Additionally, who would pay for this traffic growth? It also limits traffic at some point.
I hope it would happen after we would get our 22h/4k/12bit/120hz.

Now, you could argue that Metaverse would jump and multiply traffic by an additional 2x or 3x. Then 400GE may be needed.
Sorry, but it is speculation yet. It is not a trend like the current (declining) traffic growth.

Ed/
From: NANOG [mailto:nanog-bounces+vasilenko.eduard=huawei.com () nanog org] On Behalf Of Phil Bedard
Sent: Thursday, May 4, 2023 8:32 PM
To: Etienne-Victor Depasquale <edepa () ieee org>; NANOG <nanog () nanog org>
Subject: Re: Routed optical networks

It's not necessarily metro specific although the metro networks could lend themselves to overall optimizations.

The adoption of ZR/ZR+ IPoWDM currently somewhat corresponds with your adoption of 400G since today they require a QDD 
port.   There are 100G QDD ports but that's not all that popular yet.   Of course there is work to do something similar 
in QSFP28 if the power can be reduced to what is supported by an existing QSFP28 port in most devices.   In larger 
networks with higher speed requirements and moving to 400G with QDD, using the DCO optics for connecting routers is 
kind of a no-brainer vs. a traditional muxponder.   Whether that's over a ROADM based optical network or not, 
especially at metro/regional distances.

There are very large deployments of IPoDWDM over passive DWDM or dark fiber for access and aggregation networks where 
the aggregate required bandwidth doesn't exceed the capabilities of those optics.  It's been done at 10G for many 
years.  With the advent of pluggable EDFA amplifiers, you can even build links up to 120km* (perfect dark fiber)  
carrying tens of terabits of traffic without any additional active optical equipment.

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.

Carrying high speed private line/wavelength type services as well is a different topic than interconnecting IP devices.

Thanks,
Phil


From: NANOG <nanog-bounces+bedard.phil=gmail.com () nanog org<mailto:nanog-bounces+bedard.phil=gmail.com () nanog org>> 
on behalf of Etienne-Victor Depasquale via NANOG <nanog () nanog org<mailto:nanog () nanog org>>
Date: Monday, May 1, 2023 at 2:30 PM
To: NANOG <nanog () nanog org<mailto:nanog () nanog org>>
Subject: Routed optical networks
Hello folks,

Simple question: does "routed optical networks" have a clear meaning in the metro area context, or not?

Put differently: does it call to mind a well-defined stack of technologies in the control and data planes of metro-area 
networks?

I'm asking because I'm having some thoughts about the clarity of this term, in the process of carrying out a 
qualitative survey of the results of the metro-area networks survey.

Cheers,

Etienne

--
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