nanog mailing list archives

Re: 100GbE beyond 40km


From: Dan Murphy <dmurphy () pilotfiber com>
Date: Mon, 27 Sep 2021 10:25:40 -0400

Are you saying we could use normal QSFP28 LR4 or ER4 modules with an
amplifier in between?
Yes, that is the idea from 30,000 ft. Fun fact, the ER4 optics you mention
are amplified inside the pluggable in a very similar manner to how these
EDFA systems work.

Basically: QSFP28 100G ER <-> EDFA Amp <-> OSP/dark fiber <-> EDFA Amp <->
QSFP28 100G ER
Very simple, and from the Juniper gear's POV, there is no funny business.
All the magic happens down at layer 0.

The systems are commoditized and pretty easy to find. I saw a few people on
this thread mention Solid Optics, personally I have not heard of them, but
I would trust LB's recommendation. I've used systems by other manufacturers
in the past and wasn't crazy about them. I don't want to flame that
manufacturer since they read this mailer, and who knows, the issues I saw
might have been isolated to manufacturing issues, but I still wouldn't
recommend them.

The learning curve is pretty low, and the manufacturers of this gear are
~usually~ very eager to guide basic implementation. However, ping me off
list, or on here, if you have any deeper questions about this.

Have a good week everyone!

On Sun, Sep 26, 2021 at 12:17 AM Lady Benjamin Cannon <lb () 6by7 net> wrote:

My guess is that he was talking about the difference between a 100gbit/sec
stream of ethernet frames with no error correction, and a 112gbit/sec (or
so, depending on scheme) stream of transport with FEC (Forward Error
Correction - which is essentially just cramming extra bits in there incase
they are needed.

Ethernet has to re-transmit instead, and that can cause performance
degradation and jitter, until it just quits working altogether.   Systems
implementing FEC are much

(This is a guess, there’s a chance something else was meant by this)

-LB.

On Sep 25, 2021, at 1:55 AM, Etienne-Victor Depasquale via NANOG <
nanog () nanog org> wrote:

Bear with my ignorance, I'm genuinely surprised at this:

Does this have to be Ethernet? You could look into line gear with coherent
optics.


Specifically, do you mean something like: "does this have to be
IEEE-standardized all the way down to L1 optics?" Because you can transmit
Ethernet frames over line gear with coherent optics, right ?

Please don't flame me, I'm just ignorant and willing to learn.

Cheers,

Etienne

On Fri, Sep 24, 2021 at 11:25 PM Bill Blackford <bblackford () gmail com>
wrote:

Does this have to be Ethernet? You could look into line gear with
coherent optics. IIRC, they have built-in
chromatic dispersion compensation, and depending on the card, would include
amplification.

On Fri, Sep 24, 2021 at 1:40 PM Randy Carpenter <rcarpen () network1 net>
wrote:


How is everyone accomplishing 100GbE at farther than 40km distances?

Juniper is saying it can't be done with anything they offer, except for
a single CFP-based line card that is EOL.

There are QSFP "ZR" modules from third parties, but I am hesitant to try
those without there being an equivalent official part.


The application is an ISP upgrading from Nx10G, where one of their fiber
paths is ~35km and the other is ~60km.



thanks,
-Randy



--
Bill Blackford

Logged into reality and abusing my sudo privileges.....



--
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




-- 
Daniel Murphy
Senior Data Center Engineer
(646) 698-8018

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