From WIN to IP

The WIN specification defines an evolution of the current ANSI-41 protocols. At one level, the goal is to create better support for roaming wireless phones and to add new services for subscribers. At a deeper level, WIN promises multinetwork and multivendor support of infrastructure components and leads the industry toward distributed architecture.

By distributing network components, primarily the HLR, a client-server network emerges. Multiple switches around the globe can create sessions with the distributed HLRs without bothering home switches. This increases access speed and allows for internetworking across vendor and technology lines.

WIN + AIN + IP?Most engineers already know that wireline and wireless networks must interconnect on a peer-to-peer level. If U.S. wireless continues to grow by 30% to 40% per year, the industry no longer can be thought of as an adjunct to the wireline network. In other words, WIN and the landline advanced intelligent network (AIN) must become fully interoperable.

But WIN/AIN connectivity may not be enough. If people begin to embrace the use of their desktop PCs and high-speed Internet connections for voice communications, IP voice switches will need to play ball with both WIN and AIN. With 3G technology around the corner, who is to say that wireless voice telephony won't move to IP as well?

A number of visionaries believe IP is the answer to everything. Indeed, IP version 6, though it may take years to implement, will have provisions for isochronous connections. (Isochronous systems require a steady flow of uninterrupted data with small buffers to function correctly. These include voice, music and video.) Once the Internet delays become so small that they go unnoticed, people will be using their 'Net connections freely to send voice and video images to one another without long-distance charges.

Although some argue that the Internet never will achieve the ability to send real-time audio and video, this level of performance can be achieved on private intranets. Intranets that link district offices of large corporations are using high-speed, dedicated-access lines that see almost no delay. Add-on products to PBXs allow extension calls to be routed through IP pipes, saving these companies thousands of dollars annually.

THE WIN EFFECTAnd here is where WIN may come in. Let's assume that an office in Detroit uses a PBX with an in-building wireless solution. Station-to-station calls use abbreviated dialing, and the phones incur no airtime charges while on the premises. Long-distance calls made on the campus go through the local PBX, where a cell site and base station are connected. If the caller moves outside of the campus environment, the phone switches to the off-campus mode, using the home cellular/PCS network.

Let's assume that someone in the San Francisco office uses IP telephony over its intranet to call a fellow worker in Detroit. That worker in Detroit, however, has moved away from the office and currently is roaming in Atlanta. Now what? How does that call get from Detroit to Atlanta? How does that call cross the IP telephony/public wireless network bridge?

If WIN were equipped with the capability for IP telephony support, the situation just described could be managed. The information about the Detroit subscriber would be housed in an HLR that was an independent network element. The San Francisco's IP telephony server woulduse IP protocols to establish a connection with that HLR to determine the current roaming status of that user (now in Atlanta). The IP call then could be routed to the switch in Atlanta over the Internet and be presented to the caller in either standard circuit-switched voice or IP-voice, depending on the capabilities of the user's handset and of the local wireless carrier.

COMPLETE INTEROPERABILITYEnabling WIN systems for open IP access would provide every IP-telephony switch the ability to interoperate with wireless voice networks. If the same occurred in the landline space, all three forms of communications would inter-operate completely. At the same time, data could be moved among these network elements, providing the ability to transfer text transcripts, language translations, pen annotations and even video calls.

If you let your mind wander a bit, you also can create collaborative computing models that would require WIN/IP connectivity. For example, if a group of users wanted to share an electronic whiteboard (a product such as Microsoft's NetMeeting, for example), it could do so regardless of which networks were being used for access. Some of those users could be running the application on a desktop PC while others would be using wireless LAN-connected laptops and others using wireless phones or PDAs.

If a large number of future wireless phones are to be smart phones with Internet connectivity, local processing and screens large enough to display reasonable amounts of information, users will expect these devices to be able to handle multimedia communications sessions. These sessions most likely will be transported by IP protocols and could be originated, or terminated, by IP-telephony servers.

Today, these servers keep their own directories of user names and addresses with no regard for compliance or interoperability with AIN or WIN. Multiple protocols for connection to these servers exist, but over time the computer industry will gravitate to a common standard that probably will be interoperable with HTML interfaces.

Such interoperability provides a growing opportunity for wireless carriers. If you go to just about any major search engine and find the national white pages (People-Find), you'll find some-one's home telephone number. If you call that person, you'll be generating revenue for a landline carrier. If you search further, you also could obtain an e-mail address. These addresses are used in IP-telephony packages to place telephone calls and call conferences. Although a bit of a black art today, this form of communications is growing as network speeds improve and users become more sophisticated.

I see convergence of directories along with a convergence of communications systems. Much of what distinguishes WIN from AIN is wireless' mobility aspect. As PC users become more mobile themselves, we will see AIN begin to adopt the same strategies that now exist solely in the wireless camp. Perhaps in the end, we won't even refer to the two as separate initiatives; they will become one.

When my hotel phone rings because you dialed my wireless number, we'll know we're on our way. When the laptop in my hotel rings with a video call placed from a roaming wireless smart phone, we will have arrived.