Caution: IP Ahead

Today, carriers are making decisions based on a paradigm almost unimaginable a decade ago: Data transmissions may overtake voice communications.

According to the Yankee Group, data transmission will overtake voice transmission by the year 2000. Sprint reports that today, 73% of the traffic carried over its network still is voice, but a year from now the company estimates that traffic will be 60% voice and 40% data. By mid-2000, Sprint expects to transmit more data over its new packet-switched network than voice.

Voice services may even evolve into a free add-on product, according to some industry watchers.

"Carriers will just throw voice in for free to customers who buy broadband data services," said Mike Cristinziano, Gerard, Klauer & Mattison network software research vice president. Under this new data-centric model, packet-switched networks that were developed specifically to transmit data will have an advantage over circuit-switched networks. According to some experts, wireless carriers are behind the curve on this trend and need to step up their efforts to understand how Internet protocol (IP) will fit into their future plans and networks.

VOICE QUALITY IP telephony does have its pros and cons. The Internet, after all, was designed to carry data, so it doesn't do a good job of delivering real-time, synchronous, full-duplex communications such as the voice-focused public switched telephone network (PSTN).

"The problem with wireless over IP is the same as in landline telephony," said Ken Woo, AT&T Wireless external communications manager. "The problem is voice quality and time of transmission."

That's the catch: The public Internet is cheap, but you get what you pay for.

Fortunately, private IP networks can deliver much higher quality voice transmissions. Voice transmission is simply another kind of data packet in packet-switched networks. As long as the newest IP routers are successful at interpreting and passing along the information packets, voice quality over IP networks should be effective.

"Instead of banking on centralized switching, wireless operators should be developing networks modeled after the Internet," said Ira Brodsky, Datacomm Research president.

Wireless carriers married to INs that centralize intelligence in big switches have been reluctant to take this step. They are even more reluctant to discuss the matter.

"We are still in a very preliminary stage of evaluating IP networks," said Jeff Battcher, BellSouth Cellular manager of media relations.

Integrating IN and IP networks is an important issue facing the industry. That's why carriers don't want to show their cards.

IP would allow wireless carriers to use backhaul facilities more efficiently, and it would position them to offer many new integrated voice and data communications, such as video conferencing and document sharing. Furthermore, IP telephony will permit a digital cellular or PCS user to connect to a local gateway and complete multiple voice calls and/or data sessions without having to redial.

Stanley J. Zoltek, Bell Atlantic director of IN Applications, said the synergy between these two technologies will affect the telecommunications industry as Microsoft Windows affected personal computing.

"When Windows became available, people began creating applications based on all kinds of circumstances and needs because Windows made it easier for them to do so," Zoltek said. "It will work much the same way in the telecommunications industry. The Internet is the tool that will allow users to take advantage of the IN capability."

MAKING IT WORK Technically, integrating wireless and IP shouldn't be hard for companies not wedded to the centralized intelligence paradigm. Basically, a wireless network is a fancy computer network with RF capability. It runs on a certain protocol with data packets sent through a computer system. The packets need to be converted into a format that can be transmitted through the air.

"If you look at it just as a data packet and a computer network, the costs involved would be those to patch a server or a network into the Internet," said Daryl Sterling, Yankee Group wireless communications analyst.

There are several places you can connect a wireless network to an IP network. The switch is the first place. That already is happening, particularly in the paging industry.

Also, many wireless carriers simply could use IP infrastructures to supplement part of the network rather than building it out completely. The basic components of a network are the switch, the controller and a satellite uplink at the controller. Then the signal must come down to a base station. A connection from the switch to the controller -- usually called the interswitch network -- typically is made up of a wireline infrastructure such as frame relay. This connection doesn't have to be wireline, however. Carriers could use an IP backbone rather than build or rent the infrastructure between those two points.

"It would cost much less than building out your own network or renting the capacity," Sterling said.

At this point, the signal leaves the controller and goes to the satellite uplink. This connection from the controller to the satellite uplink also requires a landline connection. Carriers would rather not lose control of this part of the network, but if you have many switches and controllers, it may make more sense to use existing architecture such as an IP pipeline.

Lastly, the signal comes down to the actual transmitter site where the power resides. There are several pieces of equipment including the base-station controller, transmitters and receivers. This "distribution" network where the signal leaves the wireless network and goes over the satellite network, or out to transmitter sites, doesn't have to be via satellite.

Until recently, satellites have represented the most efficient and least expensive technology to widely distribute signals to several different transmitter sites. However, that could be done easily via an Internet backbone because of the many Internet points of presence available today.

Many carriers face capacity problems with antiquated legacy architectures. All of the "tags" on a data packet take up capacity by increasing the size of the actual data packet or the message being sent. Legacy systems do not have enough capacity for the additional packet information.

But advanced network architectures can use Reflex architecture to increase capacity and avoid legacy challenges. "It is kind of like the difference between sending a letter to someone with no return address or having a Fed Ex guy deliver it and have the receiver sign for it," Sterling said. "With Reflex architecture, you have that extra capacity that allows you to send a packet with very specific information on it."

DISTRIBUTING THE INTELLIGENCE Integrating wireless with IP would push network intelligence farther to the fringes of wireless networks. As wireless evolves, the intelligence increasingly is being distributed between both ends of the network. At one end is the switch, and at the other is the end-user device.

That's the trend that Hand Held Products was counting on when the company integrated FTP Software's TCP/IP technology into its Dolphin family of batch and wireless mobile computers and bar code scanners.

These intelligent devices make use of an IP backbone for wireless even simpler. The devices can tag messages and tell them where to go. Messages no longer have to travel through a switch under this configuration. Cellular phone signals must go to a transmitter, which can either look for a satellite uplink or for an IP hookup. If the message is coming out of the device and has a tag routing it to its destination number with a road map through the appropriate networks, then the "big iron" switch becomes redundant.

An integrated IP-wireless network would thus make use of least-cost routing. An intelligent device, in other words, could decideto send a large message via IP, while small messages could be sent via satellite.

That should be relatively easy for paging if not voice communications, Sterling said. Unlike voice communications, the package is predefined in paging transmissions. A paging message already has a size and is recognized immediately. It is not clear, on the other hand, how long a voice call is going to take and how much data is going to be exchanged.

Ray Dumbrowski, Comcast Cellular senior vice president of engineering and technology, said that such a scenario also holds promise for other kinds of data.

"With conventional circuit-switch transmission, you have to maintain the inventory of switches, whereas (packet switching) permits you to maintain almost a virtual switch," he said. "Because you can eliminate the number of hard switches in the network, this kind of arrangement would allow you to cut costs in the long run."

PACKET-SWITCHING PLANS But don't expect widespread applications involving the merging of IP and wireless for at least a few more years.

"We couldn't even begin to tell you how much this would cost (to build out) at this point," Comcast's Dumbrowski said.

Many incumbent carriers have taken a similar attitude: No need to rush. But new competitors such as Advanced Radio Telecom (ART) are on the horizon. ART claims to be the first company to integrate fiber-optic and broadband wireless technologies into an advanced packet-switched communications platform. ART is building IP metropolitan networks that will provide an array of end-to-end services including Internet access, data transmission, fax, video conferencing, electronic commerce and voice-over-IP on local, regional and national levels at 38GHz.

Using broadband fixed wireless, ART connects directly to the business customer's premise, bypassing the antiquated copper infrastructure. ART will extend its network into the top 100 U.S. markets over the next five years.

Even as wireless carriers continue cautious steps toward IP, they would do well to closely watch the efforts of ART and others that already are betting on IP.