March 1998

BY ERIC LARSON

Convergence — the blending of voice and data applications onto a single, typically IP-based networking structure — is today’s new networking trend, driven by the desire to minimize networking and overall opera-tions costs. But convergence can be tricky. Successfully melding varied networking technologies and applications will take flexible access products to assure branch-to-branch routing or switching over the "best" technology — whether it’s best for the application or for the economics.

With ubiquitous forewarnings that convergence in the intranet era is upon us, the danger is not so much missing the boat but being trampled in the stampede — or, more accurate-ly, being stampeded into building an insufficiently engineered corporate intranet. Just do it, but do it right. Short-sighted engineering could snare you into a riptide beneath the "tides of change," impairing the future quality and reliability of your applications.

Designs of Internet protocol (IP)-based networks are being driven by customer demand for trafficking useful applications — data, fax, voice, video, multimedia (and what-ever is next) — from anywhere to anywhere via the Internet. The conundrum is that many of these intranets are being developed before IP standards are set or application interoperability questions nailed down, so there are gambles involved even in the best-case scenarios. But competitive incentives simply won’t let the corporate world wait for all the answers before committing to the intranet arena.

TECHNICAL ISSUES
Whichever way you decide to engineer your intranet — based on Internet protocol or frame relay or perhaps ATM technology — you must consider the questions of congestion, delay, quality needs, and who and where your users are. Industry experts who have accommodated expanding applications, figured out the interoperability questions, dealt with standards, and have a networking strategy based on a unified platform to support any or all protocols, public, or private carriers — are a good place to turn for help. Separate platforms for voice, video, and multimedia are unnecessary. Reconfiguring a network to con-verge applications should oblige only software upgrades, not require you to buy new hardware and trash the old.

In the brief history of frame relay networks, by way of reference, we have learned to accommodate voice-over-frame with "any-to-any" switching, PBX-to-PBX connectivity, and PBX-to- remote office connectivity quite efficiently and cost effectively. But there remain some technical issues that must be understood and dealt with in order to make the quality of voice and video acceptable for an IP-based intranet. The fundamental technical difficulties for IP networks involve bandwidth, delay, and interoperability.

If an IP network is not engineered solidly enough to be able to nearly guarantee that a pre-determined amount of bandwidth will be there for the ensuing traffic to get through with a relatively low delay (perhaps less than 150 milliseconds) one way, then voice quality will suffer and video conferencing will experience delays and/or frame loss. This translates to longer delays and more bandwidth expended, which can cause further network congestion. (This is less of an issue in a frame relay network because there is inherently much less overhead involved.) The answer? Engineer the IP intranet such that delays are minimized and the band-width is there to support the additional real-time bandwidth needs for voice, video, and multimedia.

BANDWIDTH
Bandwidth, of course, isn’t free. It’s a common misconception that if you have an IP structure in place, you can simply throw voice over it as you would data. That’s fine until you get to a congestion point and voice quality suddenly deteriorates. The solution involves understanding the voice traffic levels that can be put on a network and making sure the network has adequate bandwidth to carry it. If it doesn’t, you’ll have to buy more bandwidth — either higher-speed access, which could be a considerable expenditure, or more CIR (committed information rate) for a frame relay network.

Bandwidth questions are even more dicey when dealing with the Internet because you have no control over the engineering. One connection may be great and the next could be a disaster. The industry is trying mightily to resolve these issues, specifically with ongoing efforts to develop a real-time Resource Reservation Protocol (RSVP) which seeks to guarantee that any given Internet call or video confer-encing link-up keeps the same band-width, end-to-end, all the way through the network for the duration of the call.

QUALITY OF SERVICE
While an intranet can give an organization the benefits of a LAN — com-mon- interface open applications like e-mail, and Internet access for employ- ees and new Web-page marketing capabilities for the company — high expectations loom for reliable Internet tele-phony and video conferencing. Also currently unsolved, however, is the ability to have directory services which translate between IP network addresses and phone numbers. This is a critical and complex function — and a funda-mental business demand. While this interoperability dilemma appears solv-able in an intranet where you have a more limited class of phone numbers and IP addresses, it remains unfathomable for global Internet communica-tions where the same level of "business class" voice quality is assumed.

STANDARDS
Interoperability standards, therefore, are a top industry priority. Communications equip-ment vendors must be able to build toward standards to ensure a rising mar-ket tide will raise all ships. Customers need to be able to pick up a telephone somewhere in the world, make a call to a gateway which converts it into an IP datagram, possibly go through the Internet, and come out at another vendor’s gateway to hit another phone number elsewhere on the planet.

TWO MODELS
The industry is currently shaking down into two different kinds of voice-over-IP models being developed simultaneously in the marketplace — the corporate intranet model and the Internet model. The Internet model sees a wealth of start-up companies basing their applications on standard PC platforms, trying to make this a pure software play. The difficulty comes when the application of these different software-based versions of voice and IP hit the ISP gate-ways, and the gate-ways try to recognize a n d understand the calls. The market must come to terms with standards involved with hitting Internet gateway points.

Corporate intranets, on the other hand, are relatively isolated from such problems. Typically built from a single vendor’s equipment, they’re much more controllable from the perspective of engineering, traffic, and congestion. That doesn’t mean they won’t get over-whelmed with bandwidth requirements if too much activity is added because of voice or video applications. It just means intranets are bet-ter understood and their problems appear manageable. The same cannot be said of the Internet model at this point.

We should also expect a shakeout between the long-distance PSTN busi-ness and the Internet telephony market. Expect stiff competition on the imple- mentation cost and pricing side, because many will rush to Internet tele-phony applications, attract-ed by the "pseudo-free" image. Despite the relatively lackluster voice quality of some, they’re still taking business from long-distance companies which won’t let the challenge go unanswered.

FUTURE NETWORKS
Note, in looking to the future, that this is not necessarily a matter of having to choose between an IP-based or a frame relay-based network. In fact, while many new corporate intranets now run on frame relay services, many applications are made to run over IP and many IP net-works are tied together over a frame relay. If your intranet is fashioned with routers capable of transporting applications either through IP or directly onto frame relay, then you have a lot of flexibility. But if your IP intranet’s routers cannot deal with frame relay and all your applications must go purely through IP, you’re limiting your enterprise in the long run.

The bottom line? Expanding your organization’s network paradigm to encompass an intranet or the Internet makes sense. Make sure your plans to get there do, too.

Eric Larson is a senior product marketing manager at Motorola Information Systems Group. Motorola is one of the world’s leading providers of wireless communications, semi-conductors, and advanced electronic systems, components, and services. Major equipment businesses include cellular telephone, two-way radio, paging and data communications, personal communications, automotive, defense and space electronics, and computers. Motorola semiconductors power communication devices, computers, and millions of other products. Motorola’s Information Systems Group, Network Systems Division, is dedicated to developing a family of high-value, cost effective WAN access devices which allow corporate customers to make effective use of public and private packet-based networks worldwide. For more information, contact the company at 508-261-4000.