Multiservice Network Dream Wide Open to Interpretation
By Peter Lambert
Multiple voice, data and
video services over a single wide area connection and a single rack of equipment provided
by a single service provider at a competitive cost–that’s the dream of carriers and their
corporate customers, both of which are currently overburdened with duplicative equipment,
service costs and network provisioning and management systems for voice, private data and
The current problem, most agree, lies with the fact that the typical business must
deploy one set of lines and equipment for voice access, separate lines and equipment for
private data, and yet other separate lines and equipment for Internet access. Further, the
wide area network (WAN) access lines themselves generally are sold in fixed bandwidth
increments, leaping from multikilobit-per-second (kbps) dial-up or integrated services
digital network (ISDN) lines to 1.5 megabit-per-second (mbps) T1 lines all the way to
45mbps T3 lines–all rarely matched closely to a corporation’s actual capacity needs.
In 1998, the dream of migrating away from this multiple "overlay" networks
model to a unified, multiservice access pipe sized to each company’s needs may be coming
into sight, as a wide array of access products enter the market with promises to integrate
voice, private data and Internet access over single WAN connections.
Yet the job will remain daunting, as carriers face a bewildering array of multiservice
access technology options.
Some emerging products offer convergence of voice, data and video at the WAN-customer
premises demarcation point, and some seek to converge services solely at the carrier’s
local central office (CO) or point of presence (POP). Some products claim to solve service
integration at the pure fiber optic networking level, while others attack it with an
emerging generation of synchronous optical networking (SONET) statistical multiplexing
gear designed to be data-aware as well as voice-aware.
Simultaneously, some vendors promise service integration within a single T1 line,
others provide ways to "bond" multiple T1s together to act as a single
multimbps, multiservice pipe, and still others pitch a multimbps digital subscriber line
(DSL) transport solution.
Whatever the capacity, many approaches also now incorporate asynchronous transfer mode
(ATM) virtual-circuit (VC) bandwidth management techniques. Alternatively, some approaches
assume that, even before they leave the corporate campus, all services, including voice,
will be integrated via Internet protocol (IP) packet switching, while others assume
services, including time division multiplexed (TDM) circuit-switched voice and IP
packet-switched data services, will be integrated at the level of frame relay or ATM
Over the next few years, service providers may find it too risky to wait for those
technological options to sort themselves out, as new and old competitors use lower-cost,
simplified access to win customers–particularly the customers who represent the 1 percent
of 180 million U.S. access lines that generate 50 percent of access revenues, as estimated
by research analysts Technology Futures Inc., Austin, Texas.
Even without cost competition, the need to integrate, or converge, access services
gradually is being forced by capacity expansion and service integration developments on
both the backbone and enterprise-campus sides of the access segment that lies between
customer and provider.
In the campus, the marriage of diversified IP application development with expanding
Ethernet capacity (to 100mbps and even gigabit-per-second [gbps] speeds) is enabling local
area networks (LANs) to integrate not only data file transfers, but also voice and
multimedia conferencing services without prohibitive delay or dropped packet problems
traditionally associated with "connection-less," shared media such as IP and
Ethernet. At the same time, in the backbone, incumbent carrier deployment of ATM packet
switching and new carrier deployment of very high-capacity, router-based SONET fiber optic
networks is enabling carriers to manage all manner of applications over a single pipe.
However, since local access networks have yet to solve multiservice and flexible
capacity challenges, most customers still utilize relatively low-bandwidth pipes cobbled
together with contracts with multiple access carriers.
"Almost any corporate network of any size involves more than one carrier,"
says Olaf Nielsen, marketing manager for ADC Telecommunic-ations Inc., Portland,
Ore.-based subsidiary of ADC Kentrox, which claims 500,000 installed T1 devices worldwide.
"It would be easier if they could get one device with a simpler management interface,
and control of bandwidth allocation for each service. The goal is to simplify the
customer’s life and shield him from all the minutiae."
Service providers share that goal. "We’re always looking for ways to improve the
cost structure for our customers, and that’s particularly true with access," says
Mark Evans, senior product manager for competitive local exchange carrier (CLEC)
TCGCerfnet, San Diego, soon to become part of AT&T Local Services following AT&T
Corp.’s acquisition of Cerfnet parent Teleport Com-munications Group Inc. last spring.
Currently, Evans says, many corporate voice and data specialists fail to coordinate
their WAN operations, and "some clients large and small aren’t yet comfortable enough
with firewalls, routing controls and filters to allow mingling of private and Internet
data on the same pipe." However, he adds, "we believe integrated access can be
right for most companies at some level, whether with voice or without it."
Consequently, CLECs and incumbents have begun to offer incremental service integration
options, such as Cerfnet’s Cerf One, which integrates Internet access into WAN frame relay
or ATM services, and Cerftone, which adds voice to that mix.
Ironically, most vendors expect to achieve simplicity and lower costs by actually
bringing more functionality closer to the customer, or as Mihir Mohanty, product line
manager for Sentient Networks Inc., Milpitas, Calif., puts it, "to do all the
internetworking–any service on any port at any time–at the edge and leave the backbone
According to Dick Drake, director of international marketing for Premisys
Communications Inc., Fremont, Calif., integrated access device (IAD) supplier for
TCGCerfnet, that’s why Premisys’ Q155 multiservice CO box integrates SONET add/drop
multiplexing (ADM), digital cross-connect, high-speed DSL multiplexing, frame relay and
"You get to a new business model by having service flexibility at the edge and the
ability to groom, concentrate and feed services to the PSTN (public switched telephone
network), Internet or frame relay or ATM networks with one box," Drake says.
Whatever the underlying technology, multiservice economics appear compelling, which
makes the access bottleneck appear an increasingly galling problem–a problem now in the
cross hairs of many manufacturers.
Says Jim Holley, vice president of marketing for the access products division of NEC
America Inc., Herndon, Va., "How convergence happens in the access network is the
battleground for the next century."
According to most vendors, more than 90 percent of WAN access occurs at T1 capacity or
less. Consequently, vendors including ADC; Premisys; San Jose, Calif.-based Cisco Systems
Inc.; Boulder, Colo.-based VINA Technologies Inc.; and Fremont, Calif.-based Carrier
Access Corp. (CAC) are attacking multiservice integration at the T1 level.
As part of its vision that all services ultimately will leave the customer’s site via
an IP router, Cisco last month unveiled LAN-based telephones, gateways and private branch
exchange (PBX) products for the campus, the fourth phase of a year-old project that has
sought to integrate voice and data communications into frame relay and ATM backbones
(Phase 1), WAN edge routers (Phase 2) and high-density LAN/WAN access concentrators (Phase
To enable multiple voice and data services over T1 lines, Cisco is providing in its
enterprise routers compression of voice over IP (VoIP) from 64kbps signals into 8kbps.
That scheme can squeeze 24 voice lines and 512kb of data into a T1 with room to spare for
additional applications, says Cisco’s multiservice access marketing director Byron
Complementary to, but not dependent on, Cisco’s all-IP vision, CAC, Premisys and VINA
incorporate both data and voice interfaces in their slim CPE access devices, along with
IP, frame and ATM outputs to the WAN.
VINA’s Business Office Exchange (BOX) T1 CPE box, for example, integrates voice
(including Class 5 CO dialing intelligence), frame relay and virtual private network (VPN)
encryption, tunneling and authorization access interfaces for secure remote access over
"We’re seeing [SBC Communi-cations Inc.’s] Pacific Bell going into a market
trial," says VINA marketing director Tom Barsi. "This kind of integrated access
is critical to incumbents defensively, because it reduces churn to less than 2 percent,
and it also answers the incumbents’ copper shortage."
The current problem, most agree, lies with the fact that the
That logic also applies to CLECs such as Intermedia Communications Inc., Tampa, Fla.,
which is using VINA and CAC integrated access devices to deliver its "Single T"
integrated T1 services. "Essentially, we’re moving the shared part of the [wide area]
network out to the customer premises," says Bob Rouse, executive vice president of
engineering for Intermedia. "That way, the protocol adaptation and routing decisions
occur at the CPE, optimizing the customer’s network as well as our own."
Unlike Cisco, Premisys and a raft of other vendors including Accelerated Networks Inc.,
Moorpark, Calif., expect that, while non-real-time applications may be integrated over IP,
real-time applications such as voice–which require guarantees of network delay and
on-time performance–will require ATM switching, with its ability to provision controlled
bandwidth VCs for any service.
"We see frame, voice and IP collapsing into service provider ATM networks, because
there’s no other technology that manages quality for multiple services and protocol
types," says Premisys’ Drake.
Counting itself the fourth-largest frame relay provider in the United States,
Intermedia expects to cover all those access options, leveraging both frame and ATM in its
backbone networks to accommodate "voice over X," including VoIP, over frame
relay or over ATM, Rouse says. In up to 90 cities, as early as next year, Intermedia plans
to introduce VoIP, which can be delivered from customer to Intermedia facilities via the
Single T service, Rouse notes. "We can go to a 300-node frame relay customer and
offer IP voice over our networks with off-net calls passing through gateways to the
While ATM figures as a multiservice foundation for the backbone segments of carrier
networks like Intermedia’s, even IP-centric Cisco isn’t discounting the extension of ATM
all the way to the customer demarcation, at least for customers demanding greater than T1
capacity. Its year-old partnership with ADC utilizes inverse multiplexing over ATM (IMA)
to bond together multiple T1 lines. IMA allows service providers to offer not only 1.5mbps
T1 and 45mbps T3 services, but also 3mbps, 6mbps, 12mbps and 24mbps access options in
IMA hides ATM management complexities from customers, allowing them to retain their
investments in voice PBXs, IP routers and frame relay equipment and know-how. At the same
time, IMA’s underlying ATM VC technology enables the provisioning–via software
command–of on-demand "virtual" connections between a customer and multiple
voice, Internet and private data WAN networks over a single pipe.
Consequently, IMA could answer pent-up demand for access greater than T1. Then, for
many customers, greater access bandwidth more easily can accommodate multiple traffic
types per connection.
Leading access and CO systems makers, including Sentient and Lucent Technologies Inc.,
Murray Hill, N.J., are leading efforts to demonstrate interoperability among their IMA
products, giving ATM new life as a multiservice access network solution.
Virtualized Access Links
For those carriers who won’t wait for a shakeout among multiservice technologies, some
key technological trends promise to mitigate the risks of deploying new products quickly.
Specifically, virtually all flavors of the new multiservice access products claim to be
built on distributed and modular computing models that yield low-cost, low-risk,
pay-as-you-grow capital investment requirements, compared with the costs of current access
Many vendors describe this distributed model as the "unbundling" of large,
multimillion-dollar mainframe-computer-like CO switches, service aggregation and
multiplexing devices into modularized components. Those components can be distributed far
and wide in carrier and customer networks in the form of distributed boxes that are priced
individually in the thousands of dollars, and which together can operate as a single,
centrally managed device.
In addition to enabling pay-as-you-grow deployments, the distributed-component approach
allows vendors to combine different technologies into single
"any-service-on-any-port" boxes that can, for example, allow a service provider
to provision IP, frame relay, ATM or voice on any given port through a software command,
without the need to move actual physical wires from one port to another.
This migration from equipment that requires physical network reconfiguration to
any-service-on-any-port equipment translates to the ability to "virtualize" the
links between the customer and the various destinations of the customer’s traffic, whether
those destinations be the PSTN, public Internet or private frame relay, ATM or IP
"TDM is very rigid, requiring that you touch wires and ports and devices to turn
up a new service," says Kevin Walsh, marketing vice president for Accelerated
Networks. "You need something that virtualizes the network so you can plug into any
service provider at the software level."
In other words, Walsh adds, "You should be able to instruct the network to
dynamically connect to the service provider you want. The local carrier’s role should be
to provide a virtual connection from the customer to the services provider–to turn off a
connection to one provider and create a new connection to another with a simple
For the service provider, this can alter the current environment in which 70 percent of
provisioning costs are attributable to people "manually reconfiguring networks or
rolling out in trucks to touch wires," he says. In theory, at least, such
software-based service provisioning would create a more rapid, less labor-intensive
process for turning up a new WAN access link at lower cost–a clear competitive advantage
for any service provider.
To virtualize access links, Accelerated Networks plans to deliver both an IAD for the
customer premises and a multiservice access platform (MSAP) for the CO. Fundamentally, the
MSAP grooms and concentrates traffic, then uses gateways among unlike networks to
virtualize multiservice connections.
Focused on unifying CO multiservice gear, two other startups, Vienna, Va.-based
Advanced Switching Communications Inc. (ASC) and Westford, Mass.-based Castle Networks
Inc., say their equipment can take in frame relay, ATM, IP and circuit voice traffic, then
either statistically multiplex each traffic flow directly to WAN destinations via IP
tunnels or ATM VCs.
On the customer side, ASC’s RBOX supports inverse multiplexing over ATM (via IMA) or
over frame relay (via multilink point-to-point protocol), as well as outputs to IP or TDM
Both ASC and Castle claim radical cost reduction, as well as intelligent multiservice
interworking. They offer their modularized CO gear as a low-cost alternative to deploying
full-blown $3 million switches, a particular need for competitive carriers seeking open
remote COs in smaller markets with unproven demand. Castle claims it can deliver more than
25 times as many multiservice ports per $10,000 to $20,000 rack. ASC claims it can cut
$50,000 T1 "common equipment" costs to $10,000 to $15,000.
"The economics of establishing a service provider footprint in a 31st or 100th
largest city require the unbundling of the central office switch or multiplexer, just as
the 1980s mainframe computer has been unbundled into distributed servers and
clients," says ASC chief operating officer and co-founder Ron Westernik. "Then
you can grow the system elegantly as demand grows."
At bottom, such "componentized" technologies could prove critical in making
the migration to integrated access equipment affordable.
"There’s a need for a media-aware front-end to core networks in the wide area, to
take all the traffic at the edge and put it into packets or cells," says Randy
Brumfield, product marketing director for TransMedia Communications Inc., San Jose,
Calif., another startup focused on providing integrated, multiservice, multinetwork
gateways to service providers. "The opportunity here is to provide a media adapter
that can deliver any media across any network at any speed."
In need of such equipment, national DSL services carrier NorthPoint Communications
Inc., San Francisco, currently guarantees zero packet loss over its networks, "an
ideal environment for multimedia," says chief technical officer Bill Euske. However,
until customer equipment with both voice and data ports appears, the service remains data
only. By the first quarter of 1999, NorthPoint and its local CLEC partners expect to begin
beta trials of such DSL-compatible, multiservice equipment for the small to mid-size
business customer sites targeted by the service. "Then in the local central office or
regional node, we need corresponding multiservice gateways with a convincing path to scale
to hundreds and thousands of ports," Euske says. "I’m only interested in
products that support a modular, distributed model that can start small and scale to very
high density for the gateway function."
Whatever the technological methods, it appears that economics and market demand are
pushing service providers to collapse multiple access lines into single lines from
customer to CO.
For those carriers who do this, the potential advantages over competitors include the
ability to automate the linking of those lines to every kind of public and private WAN and
the ability to instantly provision new voice, private data or Internet access service with
no more than a software command.
According to Accelerated’s Walsh, "The single-service provider, whether that’s
Internet access, dial tone or private networking, is a nonstarter."
Peter Lambert is features editor for PHONE+ Magazine.
.@Adtran updated its Mosaic suite this week. dlvr.it/RBMhzs
August 16 2019 @ 22:30:02 UTC
AT&T helped found the Airship project last year. dlvr.it/RBJjCl
August 15 2019 @ 23:45:32 UTC