SSS7 Bridges Internet, PSTN

But ATM Alternatives Further May Simplify Unified Call Control

Adding flesh to that vision in late 1998, Ascend Communications Inc., Alameda, Calif.; Nortel Networks, Research Triangle Park, N.C.; and other manufacturers delivered high-capacity, carrier-class Internet call control gateways based on established voice network signaling system 7 (SS7) technologies. These vendors believe that SS7 gateway systems will solve some of the immediate challenges in bridging the gap between the Internet and the public switched telephone network (PSTN).

Bandwidth Growth and Corresponding Core Router Scalability Requirements

Source: Nexabit

However, consensus on long-term visions of how voice and Internet protocol (IP) call controls will interoperate remains elusive. Potential buyers complain that, as various vendors jockey for standards position, IP gateways "don't talk to each other." In November, Science Applications International Corp. subsidiary Bellcore and Level 3 Communications Inc., Louisville, Colo., agreed to merge their two gateway control protocols and, at the same time, Nortel alone submitted to the Internet Engineering Task Force (IETF) standard-setting body a document proposing an open architecture encompassing all SS7 and IP signaling variants with the goal of fostering an open standard. While those variants remain in play, some Internet-oriented manufacturers and service providers believe SS7 has only a peripheral role in gateway controls.

Alternatively, Siemens Information and Communication Networks Inc., Boca Raton, Fla., and other switch and access device manufacturers are developing unified call control systems that combine SS7 with asynchronous transfer mode (ATM) virtual circuit (VC) switching.

For now, both pure SS7 and ATM-SS7 approaches are gaining at least a foothold in the gateway realm.

At press time, Ascend had sold its SS7 gateway to Level 3 and Thrifty Call, San Marcos, Texas. Nortel was scheduled to deliver its IP Gateway to two unnamed users of its MultiMedia Carrier Switch (MMCS). And Siemens had sold its multiservice carrier switch--featuring both PSTN and Internet call control--to competitive local exchange carrier (CLEC) 2nd Century Communications Inc., Tampa, Fla.

Those deployments represent a sea change for SS7, which until now has been used to enable a centralized service control point (SCP) server database to determine where an incoming call should go, then send out-of-band SS7 control messages to switches, telling them how to route the call. SCPs also process enhanced, intelligent network (IN) services, such as prepaid calling cards and 800-number translation, and apply them to individual calls.

This SCP architecture allows carriers to configure and update constantly changing information about services and customers--such as how much time remains on a prepaid calling card--in centralized servers, rather than updating every switch in their vast networks.

Now SS7-IP gateways are applying this centralized control model not only to voice switches, but also to Internet remote access servers (RACs), the modem banks that link data calls to Internet service providers (ISPs) and to private data networks. In short, SS7 acts as a common signaling system for tens or even hundreds of both RACs and/or voice switches.

Among initial applications, SS7-IP platforms will enable carriers to identify incoming data calls before they enter overburdened voice switches, then route those data calls directly to RACs.

With unified gateway control, CLECs and incumbent carriers (ILECs) can "wholesale RAC ports on behalf of ISPs, enabling the carrier to get part of call termination revenues, or an ISP could declare itself a CLEC and gain those same revenues," says Rod Randall, vice president of marketing for Ascend's carrier signaling division (formerly Stratus Computer Inc., which Ascend acquired Oct. 20).

In contrast to the pure SS7 approach, Siemens' MainStreetXpress multiservice ATM switch is enabling 2nd Century to effectively move the Internet-PSTN gateway down to the customer premises.

With commitments to buy 20 of the switches, 2nd Century will use Fremont, Calif.-based VINA Technologies Inc. T1 level ATM access devices and "ATM VCs to route data calls directly to the Internet, so you don't tie up your local switching fabric the way a dial-up circuit would," says 2nd Century president and CEO Michael Viren. "The VINA device moves the client services' intelligence out of expensive Class 5 switches to the edge, and that's where we get all our savings over building traditional, $6 million-to-$7 million circuit-switched central offices. Moving the gateway to the edge allowed us to install a less- expensive Class 4 gateway to the PSTN in the form of the Siemens switch."

A lack of IP gateway standards "is part of why we went with ATM, plus, for routing voice calls, the economics of IP gateways were five times the cost of a DS-0 [voice circuit] equivalent on an ATM switch," Viren adds, noting that a small MainStreetXpress switch provides capacity for 200,000 DS-0s, while a larger "terabit" version provides capacity for more than 1 million DS-0s.

Beyond simple diversion of data calls around voice switches, vendors and service providers also envision a range of new SCP-like services for data. "The SS7 gateway constitutes the first step to next-generation networks, as it opens the way for ATM, IP and other data networks to deliver PSTN-like services," Randall says.

Such IN services for IP might include network-provisioned virtual private networks (VPNs), unified messaging, multimedia conferencing, guaranteed quality of service (QoS) levels and guaranteed never-busy service (through dynamic routing around busy RAC ports), all based on SCP-like intelligence about port availability, phone-number-to-IP-address translation tables, customer service-level authorizations and the like.

Yet to enable these IN services, the traditional narrowband SS7-SCP infrastructure will prove insufficient because it "was engineered for internal and intercarrier operations, not for provisioning large-scale broadband services," says Pierre Sibille, director of advanced planning for Siemens broadband and data unit.

"You need to move from voice-oriented narrowband SS7 to a broadband superset of that protocol," Sibille says. "Then the same ATM VC setup process opens the door to introducing enhanced data services like multimedia messaging or IP bandwidth on demand."

Indeed, 2nd Century believes it can reduce the cost of providing access from $10 per application per desktop to $3 per application per desktop, because ATM unifies all services on one access line and one protocol at the customer demarcation point, creating a single gateway to all networks, Viren says. "In a data structure, telephony becomes another software application...eventually, another icon on your screen."

Core Routers Begin to Match ATM Speeds
By Peter Lambert

Despite a lot of media attention during the past year, carrier deployments of true terabit-per-second (tbps) routers still may be more than a year away. Yet several competitive local exchange carriers (CLECs) now are stepping in the terabit direction with deployments of routers operating at multigigabit-per-second (gbps) speeds.

For CLECs determined to build very high-capacity networks optimized for Internet protocol (IP) traffic, the new equipment portends high-speed router alternatives to asynchronous transfer mode (ATM) cell-relay switches that now dominate backbone network architectures. At the same time, for ATM-centric incumbents, some of the new multigigabit routing switches promise to bring increasing capacity to both IP and ATM packet forwarding over the next year.

In both ATM and IP networks, the fleet of core-routing switch vendors also suggests viable challenges to San Jose, Calif.-based Cisco Systems Inc.'s dominance in backbone routing technologies.

Startup Juniper Networks Inc., Mountain View, Calif., is leading that charge. Last September, Frontier Corp. Internet subsidiary FrontierGlobalCenter, Sunnyvale, Calif., installed Juniper's M40 multigigabit router. Since then, the M40 and Cisco's 12000 series Gigabit Switch Router (GSR) (installed a few weeks earlier) have been delivering traffic through up to eight OC-48 (2gbps) ports each over Frontier's intercity backbone data networks.

According to Alan Hannan, director of network architecture for Frontier GlobalCenter, the multigigabit routers arrived in time to handle current needs. However, facing a 450 percent annual growth in demand for network capacity, FrontierGlobalCenter will need routers with four times more capacity by next year, and four times more capacity again a year later, to keep up with its 18,000-route-mile, fiber optic network construction, complete with fiber capacity-expanding dense wavelength-division multiplexing (DWDM) equipment.

Capacity requirements are changing so fast that FrontierGlobalCenter soon will be using the multigigabit routers not only in its core "uberhub" facilities, but also as aggregation routers at the local edge of its network. "Once we have more than two or three OC-3 [155 megabits per second (mbps)] customers," Hannan says, "we want to aggregate them at OC-48."

Yet, he adds, by the fourth quarter of 1999, "OC-48 begins not working for us. We need OC-192 (10gbps) next year and OC-768 (40gbps) the year after that, and we'll be hard-pressed to get it."

If the M40 and GSR had not been available by last fall, FrontierGlobalCenter would have faced a decision between OC-48 ATM or routers capable of only OC-12 (622mbps) speeds. Even then, Hannan says, FrontierGlobalCenter probably would have chosen the slower routers.

"About nine months ago, we decided to build an IP-native architecture, because IP is where your highest growth is," he says. "And in five years, IP will be the multiservices convergence point in our connection with customers. If you force routers to feed ATM switches, that's one more layer of complexity than end-to-end IP."

Juniper, which began software beta trials with several service providers a year ago, now claims 12 paying customers, three of them in commercial deployments.

"With actual shipping product, Juniper is the most credible threat to Cisco in the multigigabit space," says Aman Kapoor, director of switching and routing for research analyst Ryan Hankin Kent Inc., San Francisco.

Still, other competitors are in the core router race:

* On Nov. 30, NetCore Systems Inc., Wilmington, Mass., delivered its Everest hardware and software for beta trials with national provider Savvis Communications Inc., St. Louis.

* FrontierGlobalCenter also is testing the IP9000 multigigabit, high-density edge aggregation router from Torrent Networking Technologies Corp., Silver Spring, Md.

* Avici Systems Inc., North Billerica, Mass., is scheduled to deliver its Terabit Switch Router for beta trials with Denver-based Qwest Com-munications International Inc. over the next several months.

* Other vendors, including Argon Networks Inc., Littleton, Mass., and Nexabit Networks Corp., Marlborough, Mass., claim beta test agreements with as yet unnamed customers.

Like Juniper, all those vendors say they are developing scalable machines to keep up with DWDM-driven capacity growth into the future.

Yet, some fundamental approaches differ among them. NetCore, for example, says its routing switch combines IP and ATM, enabling carriers to immediately deliver both OC-48 routing and ATM-based quality of service (QoS) and traffic engineering for both IP and ATM traffic. IXC Communications Inc., Austin, Texas, expects to test NetCore's switch router in early 1999, because "we're looking for integration of ATM and IP, not one technology vs. the other," says Product Manager Suzanne Aldrich.

"End-to-end service delivery means not only speed, but also enablers of QoS, service level agreements (SLAs), and an end-to-end view across the network for troubleshooting and rapid provisioning, which only ATM can currently deliver," she adds.

Ryan Hankin Kent's Kapoor projects that there will be proprietary implementations of IP QoS in ATMless networks "two years from now, when IP will have standardized QoS comparable to ATM," thanks to emerging differentiated services (DiffServ) and multiprotocol label switching (MPLS) specifications.

Some IP-centric carriers such as FrontierGlobalCenter, for example, say they're able and willing to wait that long, while IXC, Savvis and others are not. Ryan Hankin Kent suggests the wait for true terabit-plus routers will take just about that long.

Industry Players to Form QoS Promotion Forum
By Peter Lambert

Microsoft Corp., Cisco Systems Inc. and IBM Corp. are among some 60 Internet-related companies committed to the launch of a multimillion-dollar campaign to educate buyers and vendors about the benefits of emerging quality of service (QoS) technologies.

Slated for a formal launch this month, the QoS Forum will seek to broaden the implementation of QoS technologies designed to guarantee delay ceilings, availability and other performance characteristics for delivery of services over Internet protocol (IP) networks.

The forum will not seek to generate standards, but rather promote QoS standards now emerging from the Internet Engineering Task Force (IETF), including resource reservation protocol (RSVP), differentiated services (DiffServ) and multiprotocol label switching (MPLS).

Other elements of the forum's mission are likely to include the organization of multivendor interoperability testing, conferences and other efforts to educate Internet service providers (ISPs) on the business cases for implementing QoS.

"About 80 people attended our first birds-of-a-feather meeting, and we came away with a mandate to go form the effort," says Martin Hall, chief technology officer for Campbell, Calif.-based Stardust Forums Inc., an independent services company. Stardust managed similar forums to promote the implementations of Windows Sockets security technologies and IP Multicast protocols earlier in this decade.

On Nov. 23, 14 vendors and carriers formed the Multiservice Switching Forum (MSF). Led by Cisco Systems Inc., MCI WorldCom Inc. and Science Applications International Inc. subsidiary Bellcore, the MSF plans to foster common implementations of "intraswitching" interfaces, using asynchronous transfer mode (ATM) to unify all voice, packet, cell and frame switching and routing within a carrier point of presence (POP) facility. MSF will leverage existing switching-layer, adaptation-layer and control signaling-layer standards to unify POP equipment. Implementation agreements among MSF members will be designed to enable multiple vendors to plug voice, frame relay, Internet protocol (IP) and other equipment into a common ATM switching fabric that also employs multiservice controllers from multiple vendors. The goal: to make all circuit and packet equipment operate as a single multiservice switch. Other MSF charter members: AT&T Corp., Alcatel Alsthom AG, Ascend Communications Inc., British Telecom plc, Fujitsu Network Communications Inc., Lucent Technologies Inc., Nortel Networks, Siemens Information and Communication Networks Inc., Telecom Italia, Telia AB and US WEST Inc.

GST Telecommunications Inc., Vancouver, Wash., will provide West Coast access point and backbone facilities for the National Transparent Optical NetworkConsortium's (NTON's) Next Generation Internet SuperNet Program. GST's Virtual Integrated Transport and Access network will employ Nortel Networks prototype packet, frame and cell switches and routers. Potential participants in the project, which promises speeds 1,000 times greater than typical speeds today, include Boeing Aircraft Corp., NASA Jet Propulsion Laboratories and the San Diego Supercomputing Center. NTON comprises Nortel, Sprint Communications Co. and the Lawrence Livermore National Laboratories.

Sprint Corp. has agreed to lab test Nortel Networks' new Passport 15000 Multiservice Switch, which Nortel promises will be generally available in the third quarter of 1999 at $5,900 per OC-3 (155 megabits per second [mbps]) port. The switch is designed to support native Internet protocol (IP), asynchronous transfer mode (ATM), frame relay and voice services and scales to 160 gigabits per second (gbps) aggregate capacity "and beyond."

Turnstone Systems Inc. has integrated its Copper CrossConnect CX100 local loop management system with Copper Mountain Networks Inc.'s CopperEdge 200 digital subscriber line (DSL) system to demonstrate DSL service provisioning via software controls.

ADC Telecommunications Inc. promises to deliver prototype high-speed DSL (HDSL2) products that can transmit T1 (1.5 megabits per seconds [mbps]) payloads in each direction over a single pair of copper phone lines, vs. the two pairs needed for standard T1 service. As T1 demand grows at 30 percent annually, HDSL2 will relieve copper shortage, ADC says.

Doubts about Internet technology's ability to protect electronic commerce and remote access activities top the list of concerns among corporations, according to a survey of 81 security executives surveyed by Science Applications International Corp. subsidiaries Bellcore and Global Integrity. Protecting against insider attacks, assuring secure extranet connections with business partners and providing encryption and encryption key management technologies for customer access rounded out the top five concerns.

3Com Corp., Santa Clara, Calif., will co-market asymmetrical digital subscriber line (ADSL) services with BC Telecom, Vancouver, British Columbia, through the sale of 3Com's U.S. Robotics-brand ADSL modems. BC Telecom last month contracted 3Com and Newbridge Networks Inc. to supply ADSL switches, routers and modems.

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