Asynchronous transfer mode isn't winning the high-speed networking race,
But it does manage a strong showing in several vertical markets.
By Richard Adhikari, Sm@rt Reseller
Asynchronous Transfer Mode (ATM) is like a rookie
driver surrounded by seasoned Ethernet alternatives on a
high-speed raceway: It shows plenty of promise, but it
never quite manages to earn the checkered flag.
Earlier this decade, many vendors bet that ATM would
emerge as a premier high-speed networking standard
that blankets LANs and WANs. After all, proponents
argued, ATM supports data, voice and video connections
at 155Mbps and beyond.
The ATM evangelists, however, failed to anticipate the rise of Fast Ethernet and
more recently Gigabit Ethernet. Fast Ethernet solutions offer resellers and their
customers a familiar technology at a much lower cost than ATM. What's more,
per-port Gigabit Ethernet prices are expected to fall below ATM later this year,
according to market researcher Cahners In-Stat Group.
And therein lies the rub: While most resellers focus on Ethernet solutions that
grow cheaper by the day, savvy VARs are complementing their sales efforts with
ATM gear for LANs and WANs. By selling ATM solutions into several vertical
markets including finance, health care, engineering and education those VARs and
systems integrators are driving off with bigger profit margins than Ethernet could
ever offer.
Just ask GTE Corp. The service provider, with an assist from ATM pioneer Fore
Systems Inc., recently installed an ATM backbone at Texas A&M University that
supports several major research initiatives, including:
mammography imaging at the University's Institute of Biosciences and
Technology in Houston;
video streaming and desktop videoconferencing at the Center for Distance
Learning Research in College Station; and
high-speed connections to National Science Foundation (NSF)
supercomputing centers.
Speed Isn't Everything Instead of promoting ATM's speed, most of its resellers
focus on its flexibility, reliability and management capabilities. ATM has several
distinct strengths, including quality of service (QOS) and support for switched
virtual circuits.
ATM's QoS, for example, enables customers to prioritize traffic down to the end
user. At a university, for instance, a doctor viewing imaged medical records can
receive a higher network priority than a student's e-mail transmissions. And,
because ATM offers strong management capabilities, it can oversee non-ATM links
in conjunction with QoS.
Of course, Ethernet does have an RSVP protocol for QoS, but that's no match for
ATM's offering, says Forest Preston, product line manager for network adapter
cards at the computer systems division of Sun Microsystems. "RSVP is dropping
from favor, as people realize that it's at best only an approximation to guaranteed
QoS, which ATM offers," Preston says.
Flexibility ATM is also a good option for customers
who crave more bandwidth management. If an
application suddenly requires more bandwidth, it
sends in a request to the ATM network, which
responds accordingly.
This bandwidth-on-demand feature is enabled by
ATM's architecture. Unlike TCP/IP, which is based
on packets, ATM technology is based on small,
constant-sized cells that enable traffic to be
switched very quickly so fast that you can
statistically multiplex isochronous data together
with computer network traffic. That statistical
multiplexing provides for bandwidth-on-demand.
ATM's flexibility also lets customers implement permanent virtual circuits (PVC)
and switched virtual circuits (SVC). Within ATM, you can dedicate several parts of
bandwidth between two points, so users don't have to use the entire bandwidth of
the circuit. The dedicated bandwidth creates a PVC.
In contrast, SVCs offer a more connectionless-oriented service with more flexibility.
They let users change prioritization of circuits dynamically on a call-by-call basis
within the ATM environment, says Richard Stankevich, product marketing manager
at General DataComm Inc. in Middlebury, Conn. That capability lets customers
use WAN links more flexibly.
John Armstrong, chief analyst of networking at Dataquest in San Jose, Calif., says
there's been a steady growth in demand for ATM as a backbone technology over
the past four years.
Market Opportunities In addition to serving as a reliable, flexible, high-speed
networking backbone, ATM is ideal for several other uses. Timothy Hale, ATM
product marketing manager at 3COM, says ATM is "extremely successful" in the
health-care, medical imaging, education, financial and government markets, which
often require real-time communications across local- and metropolitan-area
networks (MAN).
At Florida health-care provider Health First Inc., for instance, an ATM network
anchored by ForeRunner ATM switches has cut telephone access costs by
$120,000 annually. Roughly 50 percent of Health First's voice traffic has been
integrated onto the organization's data network, according to a recent report from
Fore and Health First.
Another avenue for resellers to consider is building virtual LANs that run across the
WAN. ATM lets users build very large, flat networks, in which distributed local-area
networks are connected over the WAN to create a virtual or emulated LAN.
The appeal here? Customers can switch traffic over the WAN or even MAN instead
of having to route it. That makes for faster speeds and more manageability,
because routing can get very complex, 3Com's Hale says.
As an added plus, setting up emulated LANs over large geographical areas using
ATM dramatically cuts the cost of wide-area links. The catch: There must be a
business case for linking up the LANs. Notes Sun's Preston: "If you're talking
about an environment in which the LANs have got a minimum amount of
community interest with LANs in other areas, then the cost of ATM or even Gigabit
Ethernet doesn't justify it."
But for deep-pocketed customers who need bandwidth-on-demand and top-notch
QoS, ATM certainly fits the bill. |
