Concentrators may become standard if ATM picks up steam and port prices fall [ASND reference]
Excerpt: "ATM access concentrators, which have much faster
backplane speeds and support many similar services, are
poised to steal significant market share from IADs as early
as next year, according to a recent report from Dataquest.
wcmh.com./lantimes/98/98apr/804a037a.html
By Jill Marts Lodwig
When network managers want to migrate to carriers'
new service offerings without revamping their
infrastructures, many turn to integrated access devices. With
an IAD in place, managers can continue to use older
equipment while taking advantage of the latest high-speed
access technologies.
IADs terminate user traffic from PBXs, LANs, front-end
processors, and video codecs and trunk that information
upstream in point-to-point T-1 links to larger backbone
switches. They support frame relay, time-division
multiplexing (TDM), as well as ATM traffic over a TDM
backplane and are optimized for voice-intensive traffic.
Because IADs can combine voice, video, and data from a
single platform, managers of both carrier and enterprise
networks find them easier and more cost-effective to
manage than multiple application devices that terminate
traffic on one another. Currently, no other equipment
provides as much bang for the buck, but another device may
soon encroach on IAD territory.
ATM access concentrators, which have much faster
backplane speeds and support many similar services, are
poised to steal significant market share from IADs as early
as next year, according to a recent report from Dataquest.
Like IADs, ATM access concentrators take traffic from
PBXs, LANs, front-end processors, and video codecs and
transport it upstream to higher-powered switches. Unlike
IADs, they convert traffic to industry-standard ATM cells
and send it at 1Gbps backplane speeds to ATM switches
for transport across an ATM backbone. ATM access
concentrators are optimized for data-intensive transport at
higher speeds, including multiple T-3 and OC-3 lines.
But widespread success for access concentrators hinges on
two uncertainties: ATM spreading from the carrier
backbone to the enterprise wide area and the price per port
falling to competitive levels.
Although deployed primarily by carriers at the network
edge, access concentrators could become the de facto
standard for consolidating voice, video, and data in
enterprise networks if carriers continue to embrace ATM at
the network core. In that case, observers say that the
technology will reach the edge of, and even penetrate, the
enterprise wide area. Gartner Group Inc. predicts that by
the year 2000, 90 percent of large corporations will have
ATM deployed somewhere in their networks.
According to George Hunt, director and principal analyst at
Dataquest in San Jose, Calif., carriers' commitment to ATM
will greatly influence such an increase."We like to think that
user demands drive carrier service offerings, but often it's the
other way around," says Hunt.
Carriers favor ATM because it lets them simplify their
networks while dramatically reducing operating costs. ATM
is the only infrastructure that can support all of their service
offerings, including voice, video, and data, as well as high
transmission speeds and quality of service.
Until recently, carriers used prohibitively expensive
full-fledged backbone ATM switches in the core and at the
network edge to deploy ATM access. But because
dedicated ATM access concentrators, which are installed at
the network edge, cost only one-third as much as ATM
backbone switches, carriers can use them to make ATM
profitable for themselves and reasonably priced for their
customers.
In addition to letting carriers provide general-purpose ATM
services, access concentrators enable streamlined ATM
offerings such as Internet access, frame-relay network
expansion, transparent LAN services, and out-of-region
network expansion.
Several vendors, including 3Com Corp., Ascend
Communications Inc., and most recently Cisco Systems
Inc., offer dedicated ATM access concentrators that usually
target service providers or enterprise users. Their prices
vary from $10,000 to $90,000, depending on their support
for network and user interfaces, backplane speeds, and
expansion capabilities.
ATM access concentrators and IADs require a
complementary device at the edges of the customer's
network and the carrier's central office. The standard
configuration is now an access concentrator at the carrier
network edge, which receives traffic that has been trunked
upstream from IADs at the customer premises.
The changing environment is reflected in the way
CompuWorld Inc.--a regional service provider that offers
Internet access, hosting, voice over IP, and video over
IP--is completing the installation of its ATM backbone
network. The company is deploying Sentient Network Inc.'s
Ultimate access concentrators at its central offices and plans
to install either IADs or ATM access concentrators at
customer premises.
Jim Parks, president of CompuWorld in Sacramento, Calif.,
says that his company is steering away from IADs at
customer premises. "IADs make sense when you have
mostly solid voice traffic and very little data. But that's
changing," he says. "Price points on ATM access
concentrators are coming down quickly, and the vendors are
incorporating more and more capabilities."
Even though they're becoming less expensive and experts
predict wide-scale deployment in enterprise networks,
access concentrators are currently installed only by
companies that run some level of ATM in their networks.
The Panhandle Information Network, a consortium of more
than 70 K-12 school districts, libraries, city and county
governments, and health-care organizations, recently
connected 55 school districts through its ATM network. The
consortium is using ADC Kentrox AAC-3 and AAC-1
access concentrators on its premises to provide Internet
access and videoconferencing across 26 counties in western
Texas.
"Using these devices to run our ATM protocol over our
regional carrier's existing TDM network lets us utilize our
bandwidth without replacing core access equipment and
substantially reduces our cost," says Rusty Owens, project
manager and director of technical services at Panhandle's
regional education service center in Amarillo, Texas.
Its central site houses VTEL video equipment and four
access concentrators for videoconferencing. Three AAC-3s
link to the local carrier's TDM network, which then connects
over T-1 lines to 24 Panhandle sites. The fourth access
concentrator is used to connect to other sites housing video
equipment and Internet gateways. Each site has
videoconferencing equipment, a router for Internet access,
and an AAC-1, with which Kentrox targets the IAD market.
Although few carriers doubt that ATM can simplify their
networks, not every company is as convinced as Panhandle
that ATM is the answer for wide-area deployment. And that
attitude may spell trouble for wholesale acceptance of
access concentrators.
"Companies just started implementing frame relay in great
numbers, so they're hesitant to embrace ATM," says
Dataquest's Hunt. "IADs are popular for TDM and frame
relay."
GTE Network Services, a local exchange carrier based in
Dallas, was an early adopter of carrier-based services
delivered through IADs. The company uses Premisys'
IMAC 8000 IADs to provide network services to small and
medium-sized customers who need to integrate voice and
data.
"Integrated access devices let us deliver a variety of services
very competitively over a single or several T-1 circuits," says
Steven Dekany, senior product manager.
Dekany says he decided against using ATM access
concentrators. "Their price range is three to four times higher
than IADs. Since price is the key issue at the moment, we're
using the more traditional device."
Nevertheless, Dekany is keeping a close eye on access
concentrators and does not rule out the possibility that his
company will eventually deploy them.
But if more carriers and enterprise network managers
migrate to ATM, access concentrators may be the only
choice left. |
