This is a bit OT from VoIP, but an interesting, if not generic, article written about ATM in backbone networks. It also touches on multiple other technologies.
Enjoy, Frank C.
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"ATM Shines on the Spine"
August 25, 1998
PC Week via NewsEdge Corporation : ATM Technology
has not been the sweeping success that vendors initially
anticipated, but it hasn't been a total bust, either. While
failing to garner much acceptance at the desktop level,
ATM is being widely used for network backbones.
ATM operates at up to 622M bps and includes inherent
redundancy that can route data around trouble spots on
a network, so it's well-suited to backbone applications,
which must handle the traffic from all departments
connected to the LAN or WAN.
In November 1996, Dr. Pepper/7Up Inc. needed to
upgrade its backbone, a 10M- bps Ethernet line that
enables 750 users in two buildings to share information.
The organization evaluated three backbone options:
ATM, FDDI and Gigabit Ethernet.
Robin Hinson, a systems architect and planning
engineer at the company, in Plano, Texas, determined
that FDDI lacked a viable migration path and Gigabit
Ethernet was untested, so the company chose ATM.
By last summer, Dr. Pepper/7Up had examined ATM
equipment from vendors including Bay Networks Inc.,
Cisco Systems Inc. and Fore Systems Inc. and selected
Fore's products. "Fore offered a flexible set of products
that could be easily integrated at an attractive price,"
Hinson said.
In addition to upgrading the backbone, the company
decided to upgrade to switched 10M-bps/100M-bps
Ethernet connections running on each floor in the two
buildings to serve its desktop users. The firm completed
the network in March, and Hinson expects the new
network to meet the firm's communications needs for the
next five years.
The city of Hartford, Conn., was in a similar situation,
with fiber-optic connections forming a backbone
connecting seven agencies, such as public works and
the city library, both located within a few blocks of each
other. The city had been using T-1 connections to link
the sites, but last year started to experience sporadic
network problems as its 1,000 users exchanged complex
files.
"In a distributed environment, network performance can
be a killer," said Al Teixeira, user support manager for
the information services department for the city of
Hartford. "Because there is no consistency in the type
of files users send from place to place, a network has to
be able to handle huge fluctuations in traffic."
The city uses the I-LAN router from Olicom Inc. to
connect the agencies and decided to upgrade from T-1
to ATM connections. The process started at the
beginning of the year and has been completed at four of
the seven sites. Teixeira stated that the T-1 network will
continue to operate in parallel with the ATM links until
the transition is finished later this year.
ATM is also being used to form WAN backbones,
linking offices in different cities. Prudential Insurance
Co. of America, Inc. has 75,000 employees and operates
data centers in seven cities that house a series of
mainframes, midrange systems and PC servers
connected by 50 T-1 lines.
At the end of 1996, the company determined it could
lower its communications costs dramatically by making
the switch from T-1 to ATM because carriers price ATM
circuits lower than T-1 lines. The company examined
products from leading ATM WAN equipment suppliers,
including Cisco, Fore and Nortel Inc., and, like Dr.
Pepper/7Up, selected Fore's wares.
Prudential then had to lease T-3 lines from several
telephone companies. Bernie O'Neill, vice president of
distributed computing at Prudential, in Roseland, N.J.,
said, "We wanted to go with one supplier, but the recent
Internet growth left many of those companies in a bind.
They have been unable to build their networks fast
enough to meet increased demand."
Prudential brought up its first ATM connection early
last year and completed the transition as the year ended.
The results surpassed expectations. " During the past 18
months, we have had less than 15 minutes of network
downtime," O'Neill said. In addition, the company has
already recouped the $1.8 million invested in the new
WAN.
The company may expand its use of ATM technology.
Currently, it uses Fast Ethernet for local backbone
connections but will need to upgrade that infrastructure
later in the year. O'Neill said the organization plans to
compare ATM, Gigabit Ethernet and EtherChannel and
select one by the end of the year.
ATM lacks integration ability
Although desktops represent the most common type of
network connection, ATM has garnered only minimal
acceptance there. The city of Hartford looked at
deploying ATM at the desktop but decided against it.
"We have a mixed networking environment and would
need to run Ethernet and Token-Ring connections along
with ATM," Teixeira said. "ATM cannot be easily
integrated with other networking techniques."
Jack Armstrong, an analyst at Dataquest Inc., of San
Jose, Calif., said standards designed to let ATM work
with other networking options have been slow to take
hold.
Pricing has been another problem. Rapid reductions
have lowered switched 10M- bps Ethernet prices to less
than $100 per connection and 100M-bps Ethernet to
$200; ATM costs approximately $500 per connection.
Server networking is another area where ATM
acceptance has lagged. With the move to sophisticated,
high-bandwidth client/server applications, companies
have been on the lookout for faster connections. Fast
Ethernet has emerged as the big winner in this market
segment.
At the end of 1996, Sonnenschein, Nath & Rosenthal
needed to upgrade its network infrastructure. "Users
had started to transmit imaging and video files that were
causing network performance to suffer," said Bill Vance,
network manager at the law firm, in Chicago.
The company selected ATM equipment from Bay
Networks for its backbone connections but decided to
go with Fast Ethernet for its server links. " There were
not a lot of ATM adapters available when we made our
selection, " Vance said.
Suppliers have concentrated on Fast Ethernet adapters
because it is a more lucrative market. Winning the
desktop and server categories has meant that Ethernet
products generate more revenue than ATM wares.
The Dell'Oro Group, a Portola Valley, Calif., market
research company, found vendors sold $8.8 billion in
Ethernet equipment in 1997, compared with $614 million
in ATM devices.
However, ATM's economic picture is not completely
bleak: The Dell'Oro Group expects ATM revenue to rise
to $1.3 billion this year due to its firm hold in the
corporate backbone arena.
Paul Korzeniowski is a free-lance writer in Sudbury,
Mass., and specializes in networking issues. He can be
reached at paulkorzen@aol.com.
<<PC Week -- 08-24-98>>
[Copyright 1998, Ziff Wire]
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