Internet – Network Convergence

Virtual video conferencing, television from a telephone line, flawless quality, unlimited bandwidth. The Next Generation Internet is coming, and it's headed straight for your living room.

The NGN will change everything. In 15 years or less you will be working in a home, office, facility or vehicle in which virtually every object has its own Internet address. Everything from the LEDs that light your desk to the penny-sized piezoelectric mini-motors that slide your car's windows will be accessible over the Internet. Manufacturers will be able to track their products, automate the compilation of maintenance information, harvest diagnostic nuggets, and provide their customers with software upgrades—all over the Internet.

In as little as three years, a PIN, voice ID or other biometric system will usher you into your personal Internet portal from any PC, TV or PDA. Depending on hardware and the services you have signed up for, you will be able to conduct a virtual teleconference—one in which an object, document or patient is the focus of the image—join an online game, participate in a video distance learning seminar, or simply download the movie, sports event, book, song or lecture of your choice in seconds.

Getting from Here to There. Most of the pieces of the NGN are either in development or are already being field-tested. Foremost among them is Siemens' Surpass architecture—a software tour-de-force designed to allow traditional digital voice communications to be metamorphosed into the packets characteristic of the IP-based (Internet Protocol) data network. The result: Voice will be transmitted in the same way as data—a technology Internet insiders call voice over IP. "Surpass has been developed to bring the phone and data networks together," says Dr. Stefan Hink, who heads up product line management for Surpass. "But before carriers will buy into it, they must be convinced that this convergence can provide 100 % voice availability at the quality level their customers expect. Naturally, many aspects of Surpass technology are still being refined. However, a number of customers are already using it commercially."

The objective of achieving dedicated circuit quality in a packet world is no mean task. "The idea," explains Hink "is to cut voice and video into packets, label each packet with a destination address and priority rating, use the packet switching network to transport them, reassemble them at the receiving end, and change them back into analog form for the user." The problem is that today's data network wasn't designed to do that—at least not in real time. True to its original purpose—surviving a nuclear confrontation—the Web is extremely resilient. If a router goes down, other routers simply move traffic around it—but with one significant drawback: delay.

Figuring out how the NGN can offer real-time, high-quality voice and, by the same token, high-definition moving image transmission, is the objective of Project KING, the German acronym for Next Generation Internet components. The three-year project, which is being funded by Siemens (50 %) and Germany's Ministry for Research and Education (also 50 %), is concentrating on voice and video prioritization techniques, failure detection and reaction, and network admission control mechanisms.

Things are more complicated in an IP environment, where voice, video and data streams can share the same path. But if the line card is part of a Surpass system, it can convert your analog voice signals into a packet stream and label each packet as high priority. The stream then heads for a router, which recognizes the labels and zips them through the network in what specialists call a "virtual trunk"—a kind of express lane—ahead of competing data packets. "Nevertheless," cautions Hink, "there are different approaches to the question of labeling, but none are completely mature. I think the entire industry is at a crossroads with regard to its understanding of how all of the new network components are going to work together."

If a failure occurs anywhere along the path of a voice or video packet, it must be circumvented without causing any noticeable delay. "You can't press a refresh button on your phone if a few of your partner's words don't arrive," says Prof. Cornelis Hoogendoorn, who is in charge of Project KING. With this in mind, Hoogendoorn's team has developed a technique called "multi-path routing" that uses algorithms to distribute a data packet stream over several paths from source to destination. "We are not transmitting the same stream twice. That would overload the network with redundant information. Instead, we are distributing a single stream over several paths," says Hoogendoorn. "You can do this stream by stream or packet by packet. The point is, if one of these routes fails, you don't need to wait until the routing protocol finds a new route, because you have a second one up your sleeve." Even if a bulldozer slices a buried cable in half, the most a user would see would be a blip. That's how quickly a new route would be established.

Just how serious Hoogendoorn and his team are about ensuring the viability of their techniques in the real world is demonstrated by their lab. Packed with routers and simulation equipment, the lab has actually been able to simulate the entire U.S. telecommunications network. "We can conduct a video conference, then crank up total traffic or simulate the effects of a bulldozer cutting a line, and measure exactly what—if anything—happens to image quality," says Hoogendoorn.

Bringing Services Home. Of course, not everything you pull up on your screen has to come from across the country or around the world. In fact, a great deal of the content we will receive at home—including a vast selection of television channels—could come from local servers, thereby reducing the load on the long-haul "backbone" network. But metropolitan networks—those that serve urban areas—could become congested as more and more users opt for high-bandwidth DSL (digital subscriber line) service, which offers about 1 to 8 Mbit/s. Furthermore, just around the corner is a new service that many industry specialists are eyeing as a potential killer application: video over DSL. Thanks to applications such as tele-shopping, gaming and music downloads, DSL is already growing at 500 % per year in Germany and Japan. Add video to the DSL picture, and, depending on what the carrier charges, demand for high-bandwidth services could go right through the roof.

With a view to meeting the needs of this exciting new market, Siemens has developed a technology that will, for the first time, allow subscribers to receive all their television programming over a phone line. Known as a DSL access multiplexer (DSLAM), the system offers the potential of sharply reducing the load on metropolitan area backbones. Here's how: A subscriber equipped with a set-top box, a very high bit rate DSL (VDSL) modem (up to 32 Mbit/s), and a splitter pushes a button on her remote control for channel 75. Transmitted to a central office, the signal is multiplexed with those from, say, 1,000 other homes. The multiplexer compares the signals and finds that 97 homes have clicked the same channel. Rather than demanding 97 video streams from the data center where the carrier's servers are located, it requests only one stream, then copies the stream 97 times and sends it down each subscriber's individual line. A millisecond later, the selection appears on the subscriber's screen. Comments Product Development Head Dr. Herman Rodler, who has been involved in writing the VDSL standard, "This is a breakthrough because it allows telcos to save the cost of building a huge network to carry redundant information. And on the subscriber side it offers the potential of having a single outlet—and therefore a single bill—for all communications. It's what 70 % of users want." Rodler adds that commercial trials will start worldwide in 2003. "Personally, I see this as a killer app," he says.

Coming Attractions. Naturally, with all the information that will be pouring into our homes in coming years, it won't be long before we will want to network our communication devices. Says Dr. Holger Herzog, head of the Center for Networks and Multimedia Communications at Siemens Corporate Research in Munich, Germany, "Suppose you get a message on your mobile , which, by the way, will be the same phone you use at home, and there's a video attached? The solution will be a so-called home media server. First, you may want a short summary or a key still image of the video on your mobile. Second, you'll touch an icon on the phone's menu and have the information transferred to your PC or TV. The server will offer you the information you want, on the device you choose, at the location you select and with your personalized visualization style."

Similarly, at Roke Manor Research, a U.K.-based business owned by Siemens, researchers are developing a "home hub" system that combines advanced cell phone technology with mobile IP. "In coming years," says Business Unit Manager for Internet Systems Keith Halsey, "it will be possible to remotely view who rings your doorbell from anywhere in the world, check their credentials, and let them in to deliver a package or bag of groceries." According to Halsey, services of this kind could become a significant source of revenue for Internet service providers.

Interacting with your PC will also be a much more personalized experience in the near future. For instance, as part of an agreement with Juniper Networks, Siemens will use software and ERX edge routers from its Westford, Massachusetts facility to provide customers with a Service Deployment System—a kind of online shop for telecom services, that can be tailored to each user's requirements. One of the most interesting aspects of the service is its bandwidth upgrade button. "Suppose you're paying $35 per month for basic service, but every now and then you want to download a group of songs," explains Karen Livoli, Product Marketing Manager for Management Products at Juniper Networks. "You realize that at 128 kbit/s it would take you all night to get those songs. So you hit the accelerator and get the songs in 10 minutes for an additional fee. The point is that the more often the user hits that button, the harder it gets to go back to 128 kbit/s. So chances are that after a few months he'll migrate to a higher level of service, which provides more revenue for the ISP."

Adds Thomas Ganswindt, head of the Siemens Information and Communication Networks Group, "This empowers the user, while simultaneously reducing administrative costs for the carrier."

To ensure that the answer to this question is "yes," Siemens scientists in Germany and the U.S. are exploring a range of optical options. Probably the most profound will be the conversion to an all-optical end-to-end system. Today, the signals we transmit are electrical. But when they reach the optical backbone they have to be converted into optical signals—and then back again when they approach their destination. Eliminating this step would vastly accelerate processing.

Such a step is still years away, however, because it will require development of optical switches, routers and algorithms. Nevertheless, progress is being made in that direction. For instance, a team led by John Mansbridge at Roke Manor Research has developed RipCoreTM LightBus, a unique combination of optical technology with a new type of traffic management and routing architecture that will form the core of the next generation of routers. "In two years," says Mansbridge, "LightBus will be capable of scaling to an unheard-of 1.3 Pbit/s (1.3 · 10¹⁵ bit/s) of data. That's equivalent to all the written information in all the libraries in the United States."

Getting More out of Fiber. Meanwhile, researchers at Siemens' Hoffmann Street campus in Munich are looking at every possible way of coaxing more information through existing fibers. Today, depending on the number of lasers used—each of which produces a distinct frequency—there can be up to 160 frequencies (also known as channels) in a single fiber. Each frequency now carries between 2.5 and 10 Gbit/s. "But," says Lankl, "40 Gbit/s per wavelength is now technically feasible. In fact, we recently demonstrated this and set the world record of transmitting 7 Tbit/s over a single fiber by using 176 channels, each of which carried 40 Gbit/s. Furthermore, we are exploring systems that can operate at 160 to 320 Gbit/s per channel."

Already, fiber is the norm throughout the backbone and is growing throughout the metro nets. The next step is the home. "The last mile," says Lankl, "is all that's standing between us and unlimited bandwidth. Once that's installed, it will withstand decades of capacity increases." Interestingly, the road from the 20th century's old circuit-switched telephone system to the Next Generation Network with its as-yet-unimaginable spectrum of services leads right into our living rooms.

Arthur F. Pease

A Few Key Terms...

IP address: An IP address consists of four numbers separated from one another by periods; e.g. 204.171.64.2. Every computer connected to the Internet has such an address so that it can be unambiguously identified and packets can be sent to it. Users who log on via an Internet provider are assigned a temporary IP address for as long as they are online. Because these number sequences are so difficult to remember, domain names such as siemens.com, or worldbank.org are often assigned. The second part of an e-mail address (behind the @) is a domain name, which can be used to forward the e-mail to its destination network.

Router: Routers are the switching centers between the subnetworks of the Internet. They work like a railroad switch or an automatic letter-sorting system, reading the IP headers on the packets received and recognizing the packet's destination network or router on the basis of a preprogrammed routing table. Modern routers can communicate with one another and constantly update their routing tables automatically.

IPv6: A new generation of the Internet Protocol. Compared to IPv4—today's most common standard—IPv6 offers specific advantages, including better support for real-time video and audio. The length of the IP address has also been increased— to 128 bits instead of 32—which means it will be possible to assign static Internet addresses to a virtually unlimited number of devices.

Tobias Hahn

Meet the Organizations that Write the Internet's Standards