The future of transport in the metro area

Mark Tinka mark.tinka at
Fri Aug 2 20:10:32 UTC 2019

On 2/Aug/19 20:06, Etienne-Victor Depasquale wrote:
> Bear with me one more time as I drill down a little and spell things
> out. I've realized that there may be more than one interpretation of
> "EoDWDM". Are you referring to:
> (a) Ethernet packets in OTU frames - thereby implying an underlying OTN?
> (b) Ethernet optical SFP+ transceivers with a cable connection into a
> transponder plugging into a DWDM Mux or DWDM OADM? (no circuit transport)

Either one would count as EoDWDM, in my book.

The general use-case for OTN is to have SDH/SONET-like OAM
characteristics, but over the DWDM network.

In basic deployments, there was a time when folk argued about whether
they take LAN-PHY or WAN-PHY EoDWDM services from providers. The OTN vs.
DWDM discussion kind of falls around there, in my opinion. Considering
that almost all use-cases for EoDWDM are into router ports, where basic
day-to-day Ethernet is the cheapest and simplest option, I haven't heard
of any customers asking for WAN-PHY or OTN in the last 3 years. Not on
our network at least, anyway...

I think the costs of WAN-PHY/OTN re: OAM have been outweighed by making
the right choice in choosing an operator that is able to deliver an SLA,
back it up, and have a NOC that works well.

Now, the next step in all this that is starting to gain a bit of
traction is "spectrum", i.e., rather than take a normal grey service
from a Transport operator, have them deliver you a portion of the DWDM
spectrum so that you can run as much bandwidth as you want over their
network. Think of it as dark fibre, but lit...


More information about the NANOG mailing list