Hot Spot - Breaking Up Is Hard To Do

Posted: 07/1999

Breaking up Is Hard To Do
"Deconstructing" the Class 5 Switch
By Peter Lambert and Charlotte Wolter

What happens when a telephony carrier network has no Class 5 or Class 4 telephone switches? According to the claims of those introducing a new generation of switches, both established vendors and small startups, costs are cut in half or more, services become almost infinitely flexible and networks are scaleable from tens to ten millions of customers.

This scenario is rapidly moving from vision to reality for carriers ranging from green-field networks built from scratch to traditional carriers looking for new ways to extend the reach and services of their networks.

Leading this revolution/evolution in the central office (CO) are server-based "soft switch" technologies. They are the product of removing call-control software--the software that determines paths and provisions switch ports across a network, and that assigns special services such as call waiting to each call--from monolithic Class 4 and Class 5 mainframe hardware and placing it on distributed servers.

In the computer networks that telco networks are beginning to resemble, server architectures largely have replaced and/or extended the reach of monolithic mainframes. Manufacturers now have set out to do the same with telecommunications networks. Data routers have been specialized servers from their inception; now multiservice voice and data switches are becoming specialized servers, too.

The expected primary benefits of this infusion of telecommunications networks with distributed, client/server computing technologies include:

* The ability to enter small markets more economically with small, but scaleable, server-based switches;

* The creation of a common switching hardware "fabric" for all packet- and circuit-switched traffic;

* The creation of a common call-control and call-enhancement platform for all packet- and circuit-switched traffic; and

* The opening of enhanced feature creation to a community of third-party applications developers that is more diverse, innovative and quick to market than traditional mainframe switch feature developers.

Networking visionaries say the shift to server-based switches will make the telephone CO "central" no more. Even the leading mainframe switch makers, including Lucent Technologies Inc., Murray Hill, N.J., and Nortel Networks, Richardson, Texas, agree.

"In applying distributed switching, the 'CO' becomes a misnomer," says Christian Constantinof, senior manager of business development for next-generation networks and a chief architect of Nortel Networks' Multi-Service Gateway (MSG) 4000 Class 4 replacement and MSG 5000 Class 5 replacement switches. "Now the network becomes the switching fabric, and the peripherals become entry points into that fabric, and they're spread across the landscape."

For carriers with and without legacy time-division multiplexing (TDM) mainframe voice switches, the distributed switch systems promise a highly economic alternative to deploying mainframe switches in markets with too few potential customers to justify multimillion-dollar capital costs. Indeed, based on network studies involving six real customers, Nortel Networks claims up to 50 percent capital savings and up to 45 percent annual operating cost savings using its MSG platforms in place of traditional mainframes.

Further, such gateways are designed to switch any kind of traffic, including TDM and packet services, enabling carriers to take all voice, private data, Internet access and broadband services into their networks over a single-access switch. They also usually feature card-based scalability, giving the service provider the ability to begin with a small deployment using just a few switch cards, and add cards only when there is demand.

According to Constantinof, "CLECs (competitive local exchange carriers) want to start small, deploy gateways selectively and grow their networks with their customers." At the same time, since those gateways will work with existing Class 4 and 5 switches, Nortel's "Succession Networks" program also plans to deliver the MSG and control servers to incumbent local exchange carriers (ILECs).

Similarly, for new network builders, Lucent now offers the PathStar data shelf and access server, a multiservice alternative to Lucent's Class 5. PathStar incorporates the functionalities of a Class 5 (complete with 60 standard local call-control features), a digital loop carrier (DLC), voice over Internet protocol (VoIP) gateway, remote access server, digital subscriber line access multiplexer (DSLAM) and access router. The data shelf and telephony feature package can start as low as $250,000.

Lucent also is applying integration of data and voice switching to products for established carriers in the form of the Class 7R/E switch unveiled in April. The 7R/E Packet Driver, first introduced late in 1998, evolves Lucent's 5ESS switch to provide both voice and data services over IP or asynchronous transfer mode (ATM) networks, converting calls from circuit format into packets. The 7R/E Call Feature Server, announced May 1 to ship in the fourth quarter of this year, will deliver over packet networks more than 3,000 services and features, such as call waiting, 911 and three-way calling. It is targeted at new or incumbent service providers with networks in major metropolitan areas.

Despite the tendency of some industry observers to write off Nortel and Lucent as dinosaurs in the new soft-switched world, analyst Hilary Mine, executive vice president of Probe Research Inc., Cedar Knolls, N.J., says the two vendors have many important capabilities, not the least of which is their software expertise. Nortel, particularly, had to rewrite some switch codes extensively in the early '90s because of problems, a misfortune that may have worked in its favor.

And Lucent and Nortel are not alone.

Startup vendors staking claims to the distributed switch market include Castle Networks Inc, Westford, Mass. (recently acquired by Siemens AG subsidiary Unisphere Solutions Inc., Burlington, Mass.); Cisco Systems Inc., San Jose, Calif.; IEX Corp., Richardson, Texas; Salix Technologies Inc., Gaithersburg, Md.; Sonus Networks, Westford, Mass.; Taqua Systems Inc., Centerville, Mass.; and TransMedia Communications Inc., San Jose, Calif.

Some of the new switches, such as those from Salix, Sonus and TransMedia, are targeted initially to replace Class 4 trunk switches. Others, such as Taqua Systems' OCX "last mile switch" are targeted to replace Class 5 local mainframe switches.

The OCX comprises Class 5 switch functions with interfaces to the local copper loop, plus enhanced services on a single circuit board. An installation can have as few as 32 access lines for as little as $35,000, or it can scale to geographically distributed units capable of serving more than 10,000 lines.

"We'll play at the 100- to 1,000-port range where Lucent and Nortel can't afford to play," says Taqua President David Michaud, who adds that the OCX could provide extended reach to larger switches placed closer to the public network core.

Designed to provide CLECs in the smallest of markets with the capability to bypass ILEC networks entirely, the OCX operates as a Class 5, VoIP gateway, ATM gateway and data traffic concentrator in one box, with direct-to-backbone links for all those services.

To separate call control from the choice of transport, Taqua intends to deliver TDM, IP and ATM trunk interfaces by the third quarter of this year.

The Taqua OCX pushes CO switching functions to the edge of the network using a distributed architecture. OCX nodes can be placed throughout a carrier's network and connected as a single switch using ATM and synchronous optical network (SONET) links.

Most of these vendors claim ongoing beta trials of their systems, and some have begun to boast actual purchases. In May, for example, Englewood, Colo.-based CLEC Convergent Communications Inc. inked a six-year, $103.5 million contract with Cisco for supply of MGX 8800 multiservice access gateways and PBX (private branch exchange) core ATM packet switches (see "Portals Reinvented, IP Service Switches Could Give CLECs Hosted-App Portal Power").

According to Greg Tenant, senior director of product marketing for Convergent, a media gateway exchange will allow the carrier to manage all IP, frame relay, ATM and TDM over a single access switch, which will enable Convergent to add local voice service to its package of enterprise data and long distance resale services.

"With voice over a data infrastructure, you're decoupling call mediation and call logic from the Class 5 switch and moving that logic to servers," Tenant says. "In other words, you're marrying packet switching with call mediation."

Because voice traffic remains the biggest moneymaker among all services, Tenant says "we can pay for the infrastructure with voice over IP, frame relay, ATM--all in one switch."

While breaking mainframe hardware into switching processors distributed across a network is rapidly becoming commonplace, the task of replicating complex public switched telephone network (PSTN) call controls in a multiservice environment remains a gargantuan task.

"Even with distributed processors, you still don't have standard control of calls across disparate devices and networks," says John Strand, president and chief operating officer of TeraBridge Technologies Corp., Gurnee, Ill., which is focusing on developing common call control platforms for all manner of traffic. "I want to be able to do a data call like I do a voice call today."

To achieve that, TeraBridge is developing a Virtual Access Services Platform call-control software system that will work with any access hardware.

TeraBridge's PathMinder software, now in its third generation, incorporates management of standard DS-0 (64-kilobits-per-second [kbps]) circuit switching, interfaces with signaling system 7 (SS7) setup and tear-down of connections and call data record collection.

The question hanging over these vendors is whether they will crack the Class 5 space now occupied by the Lucents and Nortels and even Ciscos. "All these vendors have significant market opportunity," says Tom Jenkins, senior consultant for research firm TeleChoice Inc., Oklahoma City.

The smaller companies, he says, will not be able to provide the 24-by-seven support and will be fighting long-established vendor relationships.