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RE: [EFM] What Ethernet are we talking about?

As a service provider, I agree completely with your four bulleted items expressing the needs that you would like to see
addressed  by EFM technology.  We have similar needs and are anxious to see standards that are needs based rather than
just technology alone.

 -----Original Message-----
From: 	carlosal@xxxxxxxxxxxxxxxxxx [mailto:carlosal@xxxxxxxxxxxxxxxxxx] 
Sent:	Tuesday, September 04, 2001 5:25 PM
To:	Fletcher E Kittredge; ah_smith@xxxxxxxxxxx
Subject:	Re: [EFM] What Ethernet are we talking about?


Thanks for all your considerations. First of all, I don't think that you
came out as 'confrontational', as you've said. In fact, many of the
positions that you presented are currently being discussed internally at
CTBC, and I believe that every carrier, be it legacy-based or not, have
internal discussions about this also. As for the quality of the messages,
I'm the first to acknowledge that sometimes I dont do a good job at
writing; I'm working hard to improve it. I sincerely thank you for your

Warning: this is a long message, that talks a lot about some historical
reasons why some of the issues are being brought by us at the mailing list.
If you're patient, please read and be welcome to the discussion again :-).
I apologize for being somewhat out of topic, but I believe it's worth the
time spent.

Let me tell you a few points about CTBC Telecom, as it may help to bring
you a perspective of who we are. We are a regional carrier with nearly 50
years of history. We have more than 700,000 phone lines deployed; this puts
us out of the 'big guys' league, but in a very respectful position as
medium-sized, regional incumbent carrier. In Brazil, CTBC was a pioneer on
the deployment of several technologies, such as optical transmission
systems, xDSL access, cable modems and cable telephony (both through a
subsidiary). We're now actively working to understand the basics for the
next logical step in broadband access networks, and that's why I'm
following the progress of EFM.

As for myself, I work with a group that is responsible for the planning of
all the 'data networks', as we call it. We've designed in the past few
years IP, Frame Relay, ATM and xDSL networks that provide the basis for
CTBC Telecom's data networking business. I had personal experience with
packet data networks before joining CTBC; I was a partner of a small ISP
before, and I also did contract work to deploy several corporate networks,
all of them using Ethernet. In 1996, some of these networks already had
more than 2000 access points in a single building, and they just kept
scaling since then. So I'm a firm believer in the ability of the Ethernet
to scale, and to offer services that many people never believed possible
without the old and proven circuit-based technologies.

This is my first experience of working so closely with a standards group.
As such, I was surprised by the amount of information that we were able to
exchange so quickly. Part of this reflect the confidence that we have on
our ability to understand the practical issues regarding the deployment of
new technologies, specially when residential access is involved. Our recent
experiences with xDSL and cable modems is very helpful in this regard.

In 1996, CTBC Telecom deployed some of the first ADSL modems ever sold
worldwide. At that time, there were no DSLAMs, and the units that we've
deployed used Ethernet bridging. We went beyond simply testing these units;
some of them (60 units) are still in use at CTBC today, for corporate
network access. At that time, we found that the use of Ethernet bridging
brought serious scalability problems. Even with such small numbers, the
performance was affected by the broadcasts; it was also very easy to sniff
traffic, or even take control of another user's PC. As the discussion went,
we decided to take a look at other types of DSL offer. That was our second
mistake: we decided to go with a pure IP-based network, using DSL-based
point to point routers. After deploying hundreds of these units, in a time
when DSL didn't had the popularity it has today, we had to give up. The
solution is simply not scalable. At this time, we started looking at
DSLAMs. Based on our experience, we were the first brazilian company to
deploy a DSL service based on PPPoE. It seemed like a crazy idea at first,
by it is paying off, as we have now a much easier to manage service.

All these lessons sum up a lot of practical knowledge that we believe is
important to improve the state of the EFM technology. We are trying to
provide a sound basis for the access network business. As such, I would
like to highlight a few key points:

- We want to isolate the traffic of every customer from each other.
- We want to be able to scale to hundreds of thousands, if not millions, of
access points.
- We want to be able to deliver several customer-grade services
simultaneously over the same network.
- In many places of the world, we need to open our network to carry third
party services, either as 'open access', or as some form of unbundling.
That's regulations, period. Of course, you have to provide the service
provider with a clean and safe access to your network.

Many of the points above lead us to a strong 'point-to-point' vision of the
access network. That's not because of our circuit-switch legacy. It's
because of customer demand, and the fact that we (the carriers) tend to be
associated with a public service, where reliability, privacy and safety are
important concerns to address. This is the opposite of the vision that
other newer service providers have. It may work for new companies, focusing
on some specific niches. However, I believe that as such new SP gets more
mature, they will start to feel the same kind of pressure that we have.
When some customer down the farthest part of your network fills a claim
against you at the regulation agency, you're in trouble - you have to
dedicate resources to answer questions that may seem to be completely
unrelated to your contractual duties with this customer (after all, he's
always right, or so they say). Because of the public nature of the basic
telecommunications service, we learned to always play on the safe side.
That was a hard lesson to learn, and we must keep practicing it.

Carlos Ribeiro
CTBC Telecom