ETHERNET: NEW, AND BROADER, USES OF SAME
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Thread,
Robert Metcalfe must be pleased with how his child is growing up.
Several months ago I posted a number of articles and opinions here concerning the emergence of Ethernet in a new role: As a transport utility in metro and wide-area venues.
An earlier post (somewhere in the searchless depths of Last Miledom), I posted this article which I had bookmarked separately:
pennwell.shore.net
It seemed a bit awkward at the time to be viewing Ethernet in this context, but some of its attributes made sense to me. Earlier to that post, several metro area closed-ring [municipal and community of interest] architectures had been built in the Northwest. I forget just where... Seattle comes to mind, and I think that Electric Lightwave had a hand in them, but I could be wrong about that part. They mapped GbE to primitive WDM lambda [wavelength] flows.
Since then, DWDM manufacturers have routinely included the GbE interface as a standard offering.
This is an area where we will see a lot more activity, I am quite certain. In fact, I'm banking on it.
These notions were reinforced this morning by the following article from Network World (copied below). While 10GbE is still in the dream stage at this point, its forebear has already proven its salt at the lower order 1 Gig. I'd be interested in reading comments and opinions on this topic, and whether or not you feel that teaching this old dog new tricks will be fruitful. I do. Actually, I see n*GbE as a great partial (or complete, in certain venues) flattener of networks, when properly supported in the optical domain. What do you think?
Regards, Frank Coluccio
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"10G Ethernet WANs?"
August 23, 1999
Network World via NewsEdge Corporation : When
you think of WAN technologies, Ethernet doesn't
us-ually spring to mind - but it may soon.
MCI WorldCom and other service providers are
eyeing 10-Gigabit Ethernet as an alternative to
packet-over-SONET and more traditional WAN
technologies. And makers of carrier gear are
pushing for specifications in the evolving 10-Gigabit
Ethernet standard that would accelerate its use
beyond the LAN.
For example, the high-speed study group of the
IEEE is debating whether to standardize on 10G
bit/sec or 9.584640G bit/sec. The latter would match
the OC-192 rate of SONET, a widely used carrier
network technology, making it easier for service
providers to adopt 10-Gigabit Ethernet.
Carriers are attracted to 10-Gigabit Ethernet for
more than LAN transport services. Ethernet has
proven itself as a simple and inexpensive way to
build networks of various speeds. In fact, some
carriers are already using Gigabit Ethernet in
metropolitan-area networks (MAN).
As a result, Ethernet could be on the verge of
becoming what ATM was supposed to be - a single
technology that can stretch from the desktop to the
campus backbone to the MAN and beyond.
Possible enterprise benefits are less-expensive
services and easier network management because
the network could all be based on a single core
technology.
"We're looking at the impact of native [Ethernet]
interfaces and how we can efficiently transport
Ethernet across our network," says Rama Nune,
senior manager for optical and data nets at MCI
WorldCom. The company is the only major service
provider to openly discuss its research in this area,
though industry sources say others are looking into
it.
Ethernet still falls short of ATM and SONET in many
respects. Critics point out that Ethernet doesn't have
ATM's quality-of-service (QoS) guarantees, which
are necessary for real-time traffic. Plus, Ethernet
doesn't have the built-in management capabilities of
SONET to help service providers track link
problems.
But equipment vendors and service providers are
looking at ways to overcome the shortcomings.
Ethernet can get a degree of QoS through priority
queuing, for instance.
And one possibility for beefing up WAN
management is to create a "digital wrapper" around
Ethernet frames for long-haul traffic, says Joe
Skorupa, director of switching and routing at Ryan
Hankin Kent, a market research firm in South San
Francisco. "When you're going across the country,
you've got a complex cable plant in the middle and
you need some visibility into the operation of the
network," he says. "Plain vanilla Ethernet framing
doesn't give that to you."
"The key question is whether we can offer
maintainable services," MCIWorldCom's Nune says.
Error statistics, failure conditions and other
information are vital to figuring out what service-level
agreements the provider can offer and how they can
be enforced, he says.
The main reason Ethernet is being considered for
the WAN is the low cost. Ethernet gear costs
one-fifth the price of its SONET counterparts, says
Dan Dove, principal engineer of LAN physical-layer
technologies at Hewlett-Packard.
So why wasn't Ethernet considered for WAN
transport before now? "ATM was much more viable
when Gigabit Ethernet was being developed," says
Bob Grow, an engineering fellow at Intel who has
participated in the standards process for Gigabit and
10-Gigabit Ethernet. The conventional wisdom
several years ago was that ATM would form the
backbone for most corporate networks, creating
links to ATM beyond the campus, he says.
However, Gigabit Ethernet is becoming the preferred
choice for many corporate backbones.
Technically, the standards work on 10-Gigabit
Ethernet hasn't really begun. The IEEE study group
is still trying to decide on objectives, such as what
speed to endorse. This concerns Michael Bennett, a
network engineer at Lawrence Berkeley National
Laboratory, who would like to get his hands on
10-Gigabit Ethernet gear and doesn't care much
about carrier use of the technology.
"Until that [speed] issue gets resolved, I'm afraid it's
going to delay the whole process," he says. The
IEEE study group hopes to submit a project
authori-zation request for 10-Gigabit Ethernet by
year-end. |
