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Re: A suggested guiding principle for 10GbE WAN design


Based on the recent direction to develop and optimize two separate PHY's one for
the LAN and one for the WAN, I sympathize with the position that places your
application. However, I believe that this direction may actually result in lower
costs for you. My reasoning is that there are a number of applications similar
in nature to yours: those that require simple end-to-end Ethernet transport over
long distances. In addition to yours, which I will call "private WAN" for short,
I count disaster recovery and remote backup. My view is that HSSG objectives
currently in place cover these applications adequately. Specifically, those
objectives are the media/distance objectives of: 2 km SMF, 10 km SMF and 40 km
SMF. Note that these objectives are only the HSSG's best guesses at
cost/performance point and are subject to increase or decrease as the standard
is developed.

My best advice to you is to ensure that the HSSG objectives that go forward meet
the needs of your private WAN application. I am certainly happy to help you
ensure that this goal is met.

One side note is that I believe that is is inappropriate to associate a specific
coding method with the HSSG objectives at this time. Doing so may result in a
sub optimal objective.

Best regards,


"Bill St. Arnaud" wrote:

> All:
> Now that Howard Frazier has come up with a good solution for separating the
> 10GbE WAN for carriers from the LAN issues, we still need a 10GbE WAN
> solution for the rest of us.
> The guiding design principle I would like to suggest is this: "Can the 18
> year old kid who manages my LAN also manage my WAN?  Can he use the same
> test gear and management equipment for the LAN to manage the WAN?"
> Let me you a real world example:
> Many of our school boards and municipalities are deploying dark fiber
> networks.  To date they are driving the fiber with FastE or GigE switches
> and/or transceivers.  In many cases the links are only 1-5 km and so off the
> shelf equipment equipment will work quite well.  However, in every school
> board or municipality there is usually one or two schools that are 10-50km
> (sometimes 100-200km) away.  These school boards and municipalities do not
> want to have to buy special optical equipment, test gear and management
> systems for these links.  All they want is another blade or interface to
> drive to be able to deliver data to those remote destinations.  In some
> cases they will have to install one or more intermediate regenerators
> (usually just another switch).  Again they will refuse to buy special test
> gear and management equipment for just that one piece of equipment.
> This model also extends to many of corporate campus participants as well.
> In that case they usually have 2 separate drak fiber links for redundancy
> and reliability.  But again, they don't want technology that requires
> special equipment or knowledge.
> There has been a lot of discussion if using some form of SONET or SONET lite
> for 10GbE WAN.  That may be fine for the carrier market. But I doubt if it
> will work for the scenario given above. More importantly there is a lot of
> work in ITU and OIF and elsewhere to define that standard.
> I think HSSG should concentrate on the technical space of extending the LAN
> into the WAN and not the other way around.  We need and want a technology
> for the WAN that the 18 year old kid who runs my LAN can understand and
> manage without the need of special training, test equipment and management
> systems.
> Fiber is cheap, cheap, cheap.  Encoding efficiency is not a big deal for
> this customer base. 8b/10b will be just fine thank you.  So the closer we
> can remain to the LAN standards the better.
> When ( and if ) we have to connect to a carrier network to extend our 10GbE
> extreme long distances will we require the special WAN 10GbE as discussed at
> length on this list
> Bill
> Bill St. Arnaud
> Senior Director Network Projects
> +1 613 785-0426

Richard Taborek Sr.    Tel: 650 210 8800 x101 or 408 370 9233
Principal Architect         Fax: 650 940 1898 or 408 374 3645
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