Food for thought
"IS QUALITY OF SERVICE NECESSARY? AT&T drives to control net via technology but AT&T Labs researcher finds simpler is better.
By David S. Isenberg
Box: [Simply adding bandwidth could turn out to be the cheapest
approach.]
AT&T carries the burdens of incumbency in a world exploding with
disruptive technology. My concept of a Stupid Network tries to
explain the disruptions that telcos must face, but AT&T still
doesn't seem to get it.
Recently Dan Sheinbein, AT&T's vice president of network
architecture & development, told the Star-Ledger (Newark, NJ)
that the Stupid Network has "not been a particularly active area
of discussion" at AT&T lately. Even more recently, Sheinbein
told me, "On balance, AT&T's network is getting smarter."
To me, the Stupid Network - the dumb transport component of
people's applications, designed simply to "deliver the bits,
stupid" - is a consequence of the new abundance created by
technology's headlong spurt. It's enabled by the Internet
Protocol (IP). (See isen.com for details.)
AT&T Chairman Mike Armstrong says he's embraced IP, but his
strategy is clearly "intelligent." He says that if AT&T
controls the interfaces, specifications, protocols, standards
and platforms of the network, it can weave them into a set of
seamless services. If AT&T could pull this off, it would be
able to hold back the rising tide of commoditization and reglue
the delaminating value proposition. But to do that, somehow
Armstrong would have to get AT&T back into the equipment game,
stamp out IP, and repeal Moore's law.
THE APPARENT NEED FOR QUALITY OF SERVICE
At the edge of Armstrong's awareness, AT&T Labs mathematician
Andrew Odlyzko is researching the economics of networks. He is
no Stupid Network ideologue. In fact, he used to believe that
the Internet needed such "intelligent" complications as Quality
of Service (QoS) and differential pricing. Both of these make
networks treat different kinds of data differently.
But now Odlyzko's research has led him to the conclusion that
simpler is better. Odlyzko, who came to Bell Labs Research 23
years ago straight from his MIT doctorate, has convinced himself
that simply adding bandwidth could "turn out to be the cheapest
approach when one considers the costs of QoS solutions for the
entire information technologies industry."
Internet telephony, introduced in 1995, made the apparent need
for QoS acute. Until then, Internet traffic consisted of email
and file transfers, and then web page information. For these
applications, fast transmission is nice, but delays do not make
them unusable. Not so with Internet telephony - people just
can't have conversations when there's more than a few hundred
milliseconds of delay.
Differential pricing is the first cousin of QoS. If you have
different levels of service, you need some motivation for people
to use the lower-grade service. Otherwise, the argument goes,
people will always use the best service whether they need to or
not.
But now Odlyzko thinks that even simple QoS schemes may be too
complex. Two years ago, he proposed a very simple QoS plan. It
used only differential pricing. He called it Paris Metro
Pricing (PMP), after the Parisian subway system of letting
people who pay more ride in "first class" cars. These cars are
physically identical, but less crowded only because they cost
more. In Odlyzko's vision, a PMP Internet would have two
identical, parallel channels, and one would be designated "first
class." It would cost more, so it'd have less traffic and
provide better service. But Odlyzko now says that administering
parallel channels would add more complexity than users or
service providers desire.
100 LANE HIGHWAY, A FEW FAST CARS
Lightly loaded networks don't need QoS. They're adequate even
for Internet telephony. Odlyzko found that on most data nets,
traffic is surprisingly light. (His analogy for the typical
corporate Intranet is "a 100-lane highway [for] a few fast
cars.") Also, he says, other work showed only 40% of Internet
congestion is due to transmission bottlenecks, and only a very
few choke points are to blame.
As intelligence migrates to the edges of the Internet, so does
network administration, Odlyzko says, "where it is wastefully
duplicated," at great expense because it requires human
expertise. He concludes that, "The complexity of the entire
Internet is so great, that the greatest imperative should be to
keep the system as simple as possible. The costs of QoS or
pricing schemes are high, and should be avoided . . . we should
seek the simplest scheme that works . . . "
And that simplest scheme, Odlyzko says, involves flat rate
pricing and over-provisioned, lightly loaded networks with a
single grade of best-effort service. This scheme takes
advantage of rapidly improving routing and transmission
technologies, and it doesn't mess with any of the properties
that made the Internet great. But it'll be a hard one for AT&T
to control.
[The article above appeared as Intelligence at the Edge #7,
which is Isenberg's monthly column in America's Network, on
March 1, 1999. Odlyzko's work can be found at
research.att.com. Isenberg (http://isen.com/)
thanks Jock Gill (http://www.penfield-gill.com) for comments on
an earlier draft. Copyright 1999 Advanstar.]
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Obviously this has major implications for xDSL, not the least of which is lifespan, but perhaps more importantly, that backhauls of T1's are just asking for obsolescence the moment they are implemented for DSL customers."
-- Stafford "Doc" Williamson
WinfoTech Corp. -- creators of the MAQUE streaming video service
maque.net
docw@maque.net
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