article

Nortel Updates Switch Platform with OC-3 Connection

Posted: 12/1998

Networks

Nortel Updates Switch Platform with OC-3 Connection

By Peter Meade

While
the direct optical connection is a move toward "more equals more," the DMS-SPM
announcement also carries several equally attractive "less-is-more" features.

In the heated race between the elite switch makers, Nortel Networks, Mississauga,
Ontario, recently put itself in a better position to compete with rival Lucent
Technologies Inc., Murray Hill, N.J., by introducing a peripheral services platform that
integrates a synchronous optical network (SONET) OC-3 interface and echo cancellation into
its popular digital multiplex system (DMS) switches.

Called the DMS-Spectrum Peripheral Module (SPM), the offering is aimed at delivering
additional functionality to Nortel switches in the same manner that Lucent upgraded its
ubiquitous 5ESS switch a year or so ago.

According to Tom Dowell, Nortel director of strategic hardware programs for carrier
networks, the DMS-SPM makes the DMS the first switch to have an integrated optical
interface with echo cancellation functionality. Before this, the switch had only a T1
interface, he says.

While the direct optical connection is a move toward "more equals more," the
DMS-SPM announcement also carries several equally attractive "less-is-more"
features. By integrating echo cancellation functionality, Nortel no longer needs to
provide a multitude of standalone network elements, such as digital cross-connects and
multiplexers, says Michael Evans, Nortel senior SPM product manager.

"Everyone knew Nortel would come up with something," says Michael Arellano,
principal with Degas Communications Inc., a New York-based consultancy. "It’s nice to
see Moore’s Law finally catch up with the CO [central office]. We’re dealing with
sophisticated equipment, which certainly can’t be rebooted."

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Image: Operating Cost Reduction

The OC-3 interface, which supports up to 4,032 DS-0 (64 kilobits per second [kbps])
channels with two DMS-SPMs, also takes up much less space–by four to 6.5 times, Dowell
says. While the product is aimed at interexchange carriers (IXCs), the space savings
should be especially significant to competitive local exchange carriers (CLECs), which
must rent Beverly Hills-priced collocation space from incumbent local exchange carriers
(ILECs). The new offering also is crafted for frontal access, another plus that represents
easier workmanship for the collocation crowd and a feature currently not found abundantly.

"The front-access cabling design permits simpler maintenance practices,"
Dowell says. "It also lets providers install system frames back-to-back, which makes
better use of available floor space."

Topping the list of less is that the new, integrated system promises an overall cost
cut of 30 percent, Dowell says.

DMS-SPM will provide an optical OC-3 (155 megabits per second [mbps]) interface for any
of the switches in Nortel’s DMS family, ranging from the DMS-100 to the -200, -250, -300
and -500, which can be used in local, tandem, long distance or international gateway
applications.

MCI WorldCom Inc. is the first IXC to beta test the new offering, with a trial that has
been underway since October, according to Dowell. If all goes as expected, the carrier is
expected to roll out the DMS-SPM technology throughout its international network over next
year, he says. While the initial trial involves a DMS-250 in a long distance application,
MCI WorldCom and an undisclosed number of other service providers are scheduled for
DMS-100 beta tests in the first quarter along with the first DMS-500 test, Dowell adds.

The trial puts MCI WorldCom a step closer to deploying the world’s first fully optical
network, says Jack Walters, vice president of network systems engineering for MCI
WorldCom. The potential cost savings of 30 percent are equally attractive, he adds.

icon.gif (618 bytes)
Image: DMS-SPM Attributes

While DMS-SPM’s early stages are focused on an OC-3 interface to the switch, Nortel has
asynchronous transfer mode (ATM) and primary rate interface (PRI) enhancements in the
development stages. They should become available sometime next year, Dowell says.

Such plans should fit well with IXCs’ plans, says Degas’ Arellano. "Carriers are
looking for ways to integrate ATM and IP (Internet protocol)," he says. "This is
the first step toward making the switch a giant server on an ATM and/or IP network."
This move positions Nortel well for when carriers take their existing DMS switches and
migrate to ATM or IP offerings.

While Nortel may be playing catch-up on some fronts with this release, Arellano says
the announcement provides a much "more forward-looking" perspective than
Lucent’s approach for adding an OC-3 interface to its switch. While he cautions that
Nortel did not release any real-life technical details on the nuts and bolts of the
interface, Arellano praises Nortel for its truly direct connection. In contrast, Lucent
requires a piece of gear between its Digital Network Unit-SONET and the ATM/IP network.
Even though Lucent’s approach may require extras, and therefore additional costs, he says
the result delivers no strong advantage for either party.

"Both Nortel and Lucent are headed in the same–and the right–direction,"
Arellano says. "And that is what’s most important."

Nortel also is looking ahead smartly by opening the switch to let third parties build
applications for the SPM platform, says Nortel’s Dowell. Tellabs Operations Inc. already
has developed an echo cancellation module for the SPM. The Lisle, Ill.-based company was
able to deliver the product quickly due to its summertime merger with Coherent
Communications Systems Corp., which subsequently beget the formulation of Tellabs’ Network
Enhancing Technologies Solutions (NETS) Group, which developed the product with Coherent
technology.

While Nortel has its own echo cancellation products, Tellabs contributed to the
announcement because Nortel is not noted for providing world-class audio quality, says Jim
Grzyb, Tellabs director of marketing. The resulting solution enables service providers
that have experienced a higher level of audio quality to enjoy all those benefits along
with a higher order of integration through Nortel.

"The circuit-switched world is going to be around for a while," says analyst
Arellano. "[The migration to a fully packet-switched network] is going slower than
anyone says. The hype is way ahead of itself." But when the hype becomes reality,
both switch makers will be ready, he adds.

Peter Meade is Executive Editor of PHONE+ Magazine.


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