"It's Access Stupid"
[All,
This is a bit off topic to VoIP.
No, this is not mine, although it touches on the same theme. Not a direct hit, but close enough to cause discomfort. Guess I'll have to change the title of my report which, up until now, was titled "It's No Longer the Bandwidth, Stupid, It's the Ports!" ;-)
Enjoy, Frank Coluccio]
September 30, 1998
Network World via NewsEdge Corporation : One bit of
buzz about the newest remote access technologies is
absolutely true: Faster is better.
Users, from the casual Web surfer to the work-at-home
engineer, want their downloads to fly. In response,
vendors are pushing faster and faster technologies, the
two most dazzling of which are digital subscriber line
(DSL) and cable modems. Vendors in both camps w ould
have you believe these technologies are locked in a
death grip in a winner-take-all battle for dominance.
But don't count out well-established alternatives such
as analog modems, which have been boosted to support
speeds up to 56K bit/sec , and ISDN. In fact, the Gartner
Group projects that by 2004, half of remote access will
still be done by analog modems, with ISDN g rabbing
more than 30% and the rest being shared by DSL, cable
modems and other technologies such as wireless local
loop.
You should scrutinize all of these options to find out
what's real, what's not and what's best for you.
Delirious over DSL
Some of the loudest noise in the remote access market
comes from the purveyors of DSL services, primarily
start-up carriers and aggr essive ISPs. Next year, expect
to see the regional Bell operating companies make a big
push into this market, which so far can be me asured in
hundreds of thousands of lines installed.
DSL takes a common copper phone line and adds a
screaming data pipe that supports 8M bit/sec
downloads. What's more, you can use you r regular
telephone at the same time over the same line.
At least all that is true for one form of DSL - asymmetric
DSL (ADSL) - working under ideal conditions not likely
to be found in the real world.
So if you have a good-quality copper line that's not too
long and doesn't have any other phone lines running off
it, ADSL might prov ide you with full 8M bit/sec
downloads. But keep in mind that you'll also need to
add a filter to keep the voice and data channels f rom
interfering with each other, and make sure that the line
doesn't get bundled too close to a T-1 service in the
carrier network.
If all that doesn't make DSL sound challenging, consider
that there is a whole alphabet of other DSL flavors to
pick from - HDSL, HD SL2, IDSL, RADSL, SDSL and
VDSL. Each option works at a different speed and
requires different hardware than the others.
While the various flavors of DSL are not interoperable,
you don't have to worry about that when you buy a
service. The carrier you c hoose will provide all the
necessary gear or tell you exactly what to buy. The
problem comes after you own the DSL modem for your
en d, then change carriers. The modem you own might
not work with the equipment your new provider uses.
As a result, vendors and carriers are making a big push
to standardize a form of DSL that delivers less but
delivers it more reliabl y to more potential customers.
Known as DSL lite, the technology is designed for
downloads that max out at 1.5M bit/sec. DSL lite pr
omises to work across longer phone lines than other
forms of DSL and also eliminates the need for a filter to
separate the voice cha nnel from the datastream.
Vendors say they hope to have standard DSL lite
modems on the market by Christmas. PC makers,
including Compaq, say they are interes ted in shipping
their boxes with DSL modems installed.
DSL has already turned out to be a fast, inexpensive and
reliable remote access alternative for Bill Yundt, vice
president of networ k operations for WebTV.
The DSL service WebTV buys from Covad
Communications in San Francisco is just as fast, and
less expensive, than ISDN if the remote u ser is online
for more than 10 hours per week, Yundt says.
Plus, if the line is good enough, Covad can boost the
bandwidth in increments as users require, he says.
"With ISDN, you're stuck. Y ou're not going to go any
faster without a lot of work," he says.
DSL is a dedicated service, so remote users need to be
linked directly to the corporate network or to an ISP,
which in turn connects the users to the corporate site.
WebTV buys a T-1 line from Covad that enables remote
users with DSL connections to access WebTV's central
site. Remote users do not have to dial in, so they feel
like they are on the corporate LAN, Yundt says.
Cable modem mania
Like DSL, cable modem connections also eliminate the
need for dial-up lines. Sold by the same people who
serve up your cable TV serv ices, cable modem service
can connect users to the Internet at speeds up to 10M
bit/sec under ideal conditions. The market is young,
with only hundreds of thousands of lines sold.
Customers whose machines are outfitted with cable
modems tie into the cable provider's switching office.
From there, the provider co nnects users to the Internet,
and users then access the corporate network via an
Internet connection.
Unlike DSL, the cable access link that the customer ties
into is shared. This means the bandwidth available to
any one customer can vary depending on how many
other users are logged on at the same time.
The shared nature of cable networks is a security
concern for some users. "You have more suspicions
about security," Yundt says.
Recognizing such suspicions, the cable industry is
developing a voluntary encryption standard
to protect data from being pilfered even if it is
intercepted.
For those customers who are interested in using cable
modems, service availability can be an obstacle. Most
cable networks are not w ired to handle two-way traffic,
so their owners either offer no cable modem service or
use a technology that requires the remote use r to send
uploads via a regular phone line.
But in areas where cable modems are available, they
have proven to be inexpensive and reliable. That's been
the case for about 100 f ull-time telecommuters at
Compaq's offices in Massachusetts, according to Larry
Wilson, a consultant in the company's remote access
program.
"For $40 per month for unlimited use, we said, 'Gee,
you're not going to beat that for one and a half
megabits,'" Wilson says. While MediaOne, Com-
paq's service provider, claims that its offering supports
a maximum speed of up to 1.5M bit/sec, Wilson says he
has never checked wh at his users actually get. "We
have not gone out and measured the speed because we
haven't had any complaints," he says.
One reason Wilson went with cable modems is that DSL
is less common in his area. Conversely, DSL user Yundt
says cable modems were n ot an option in his area.
Availability is becoming less of a problem for both
technologies, though. Service providers are
aggressively building DSL networks, and cable
companies are busily retrofitting their networks
to handle two-way modem traffic. DSL can be offered by
just about any ISP that wants to make
the effort, but users should consider whether such
companies have the resources to provide the support
that undoubtedly will be need ed for such a new
technology.
Covad, a DSL competitive local exchange carrier, for
example, is backed by millions of dollars in venture
capital. "They specialize in corporate customers. They
have no distractions," Yundt says.
Cable companies are well-established, but most are
already strapped for cash, so it's difficult to predict just
how fast their modem service rollouts will go.
Dial-up options
When dedicated connections are not available, analog
or digital dial-up suddenly can become attractive. The
tried-and-true analog di al-up modem has been pushed
to what most experts agree is the theoretical speed limit
of 56K bit/sec. ISDN, the digital dial-up alte rnative,
stretches the bandwidth a phone line can handle to
128K bit/sec.
The beauty of analog modems is that they are so
flexible. They can work from any phone, anywhere in the
world, and work with just ab out any other modem.
The coming of 56K bit/sec modems has turned the staid
world of dial-up access on its ear by enabling regular
phone lines to support downloads at speeds close to
the 64K bit/sec provided by a single ISDN channel.
You should know that although they're called 56K
bit/sec modems, these devices really can only support
56K bit/sec in one direction. And they can't actually go
56K bit/sec over U.S. public phone networks because of
a Federal Communications Commission limit on how
much power carriers can use on phone lines.
Like so many network technologies, 56K bit/sec
modems had been stuck in the middle of a standards
war. But with a standard finally h ammered out, the
market appears to be calming down to the point where
the price of a 56K bit/sec modem is down to about $100,
roughl y the same as for a 33.6K bit/sec modem.
Northwest Multiple Listing Service in Kirkland, Wash.,
is among those companies for which analog modems
still make the most sense.
"Anywhere that there is an analog phone line, people
can dial in," says Jeff Banks, technical support manager
for the company.
Faster connection options, such as cable modems and
DSL, are not widely available in his area, Banks says.
ISDN, he says, is just to o expensive.
And that's not the only problem with ISDN, which has a
long history of trouble that started when the technology
got too much hype to o early. It was supposed to be the
new plain old telephone service, only it was all digital.
ISDN could be used as two 64K bit/sec c hannels per
line or one fat 128K bit/sec channel. The technology
would handle either voice or data or voice and data
simultaneously.
It sounded great, but ISDN had two major problems. It
cost carriers about $500,000 per switch to upgrade to
ISDN, and once they did, provisioning service was
often a chore.
Depending on the local tariff, ISDN can work out well,
though, according to Jeff Fidler, a senior software
developer at IntraACTIVE, a software developer in
Washington, D.C. His company connects remote
workers to the main office via ISDN Basic Rate Interface
lines using an ISDN Centrex service from Bell Atlantic.
The service makes all the remote phones seem as if they
were connected by a PBX a nd allows features such as
three-digit dialing among remote users, he says.
As newer technologies such as DSL and cable modems
become more common, ISDN sales will decline, predicts
Bob Larribeau, director of the California ISDN Users'
Group. He notes a Pacific Bell filing that shows 30,000
ISDN users in California dropped the service in 1 997.
"ISDN is the clear choice when you can't get anything
else, which makes it a good choice for a lot of people,"
Larribeau says.
That is a piece of reality to hold on to as you assess
your remote access options; you will not be able to get
the ideal technology at all sites. So be prepared to pull
together remote access networks based on whatever is
fast, available and affordable. l
<<Network World -- 09-28-98, p. 89>>
[Copyright 1998, Network World]
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