Product Review: Finally going live with voice over IP

Network managers have long awaited practical voice-over-IP (VOIP) solutions. VOIP promises to ease network management and decrease costs by converging a company's telephony and data infrastructures into one network. And a VOIP solution implemented at a company's headquarters with far-reaching branch offices can save tremendous amounts of money in long-distance phone bills, provided that solution delivers POTS-like voice quality over the Internet.

Fortunately, the wait for VOIP may finally be over -- if you are willing to implement immature technology, perhaps even replacing your PBX system with it. Saving money on long-distance phone bills may be appealing enough for many organisations to deploy VOIP now, rather than wait for it to conquer current management and deployment issues, such as unreliable voice quality and incompatible hardware.

Vendors of all sizes, from networking powerhouses such as Cisco to hardware manufacturers such as Dialogic to start-ups such as AltiGen, are rushing to market with VOIP products. In this burgeoning market, vendors are targeting organisations with small to mid-size networks at each branch office.

Despite the availability of good VOIP solutions, many challenges remain for VOIP networks. In addition to management, quality, scalability, and reliability issues, you must come to terms with network equipment problems. Devices, including network interface cards, PBXes, routers, and switches must support, integrate with, or be compatible with the VOIP product you choose. Vendors now offer systems that work only with their hardware, but they are trying to make their equipment integrate with others' hardware.

With this Test Centre Analysis, we wanted to find out if VOIP is truly ready for the enterprise in terms of its voice quality, ease of administration, scalability, and reliability. We examined two types of VOIP technologies, getting hands-on experience with two popular products, AltiGen server-based AltiWare and TouchWave's all-in-one WebSwitch 1608IP.

We found that the primary benefit VOIP offers now is that it will save money on branch-to-branch long-distance bills within the United States. Companies with overseas locations will profit the most when, in the near future, ISPs offer international VOIP services. And in the long run, when the hardware becomes more compliant, VOIP will let you manage one infrastructure.

Because most VOIP products are currently aimed at small to mid-size organisations and companies starting to build their infrastructures, they will find the most success implementing VOIP now. Large corporations heavily invested in costly networking equipment will likely make a slow transition into the higher-end VOIP solutions. But any IP telephone infrastructure implemented now will lay the framework for the convergence of voice, fax, video, and data.

How VOIP works

VOIP gateways are designed to convert voice from the packet domain to the circuit-switched domain. VOIP solutions use a digital signal processor (DSP) to process the voice data, preparing the voice sample for transmission by compressing voice and removing jitter. The VOIP equipment must comply with the H.323 standard defined by the International Telecommunication Union, or ITU.

In a traditional infrastructure, calls get routed through a PBX and out to the local regional Bell operating company.

When a VOIP solution that works in conjunction with the PBX is added, local calls are routed through the PBX and voice calls are routed through the VOIP solution. The voice calls travel through the company's backbone and out a T1 line, and then either an ISP or the Internet transmits the calls to their dedicated locations, which currently must receive calls with the same solution that is used to send calls.

Three kinds of architectures

Private, or enterprise, networks are typically not as large or scalable as ISPs' networks, so the VOIP solutions appropriate for your network will likely be less expensive than, and will not offer, the advanced management and billing capabilities of the highest-end systems.

VOIP solutions are available in three different architectural technologies: cards inserted into a server; solutions, such as switches, that replace PBXes; and gateway servers.

Giving mid-range VOIP a whirl

We looked at two different types of VOIP solutions that target small to mid-size organisations: AltiWare, a card-based system, and the WebSwitch 1608IP, a switch solution.

AltiGen AltiWare is the first to reside internally in a Windows NT server. AltiWare IP R2.1 software and Triton DSP boards add integrated VOIP capabilities to AltiGen existing phone system.

The TouchWave solution is a newcomer to the VOIP market. Its WebSwitch 1608IP is a PBX and auto attendant that provides an integrated VOIP gateway feature as well as voice mail capabilities.

The third type of VOIP architecture, which targets large enterprises and ISPs, includes Cisco Access analog gateway, Nuera Access Plus F200ip Gateway, and VocalTec Telephony Gateway Series 120. No more than 10 vendors offer these high-end solutions, and it is the least developed corner of the VOIP market.

As the VOIP phenomenon spreads, visions of its success will continue to grow. Today's gateways and other network equipment necessary for running VOIP are not yet fully interoperable, and vendors have many deployment hurdles to leap. However, they are diligently working on these issues and will make considerable improvements in the near future.

Long-distance and telecommunications carriers will lead the pack, corporations with remote geographical locations will follow, and ISPs offering VOIP services and local exchange carriers will jump next on the VOIP bandwagon.

But VOIP is just the beginning. As communications technologies converge, IP will carry video and multimedia conferencing over the Internet on a single network. VOIP has many challenges to overcome, but when it does, the benefits will be tremendous.

AltiGen AltiWare

Many telecommunications vendors are feverishly working to perfect voice-over-IP (VOIP) technology and provide a system right for your network. If you are willing to take the plunge into VOIP now, you can choose from several vendors offering three basic types of solutions: server-based, switches, and gateways.

Of course you will want an easy-to-install VOIP system, and if your environment is primarily Windows NT servers, the best solution for you may be one that integrates with Windows NT.

Leading the server-based VOIP solution market is AltiGen Communications, so we loaded one of the Test Centre servers with the AltiWare VOIP gateway, an internal Windows NT product.

The AltiWare IP R2.1 software and Triton digital signal processor (DSP) boards together add integrated VOIP capabilities to AltiWare's existing phone capabilities, which let telecommuters, remote workers, and branch offices function on one corporate phone, voice mail, and e-mail system.

We tested AltiWare by configuring two Windows NT servers with AltiGen hardware and software. To simulate a company with two branch offices, we used the Test Centre's Digital Subscriber Line for the San Francisco branch office segment's connection and the T1 line for the New York branch office segment's connection.

Installing the AltiWare IP software into a Windows NT 4.0 Server was quick and easy, and it integrated flawlessly with Open Edition, AltiWare's administrative utility. After we completed the system and trunk configurations, we configured our users' extensions. It was then time to pick up the telephone.

We used a phone on the California trunk to call one on the New York trunk. We were happy with the good voice quality, and we encountered little latency while talking on the phone.

To the end user, tasks such as placing public switched telephone network, commonly known as PSTN, or VOIP calls were seamless and easy to execute -- just as you would expect from using the telephone.

Because the AltiWare solution is PC-based, it is not as scalable as some of the higher-end VOIP products that replace a traditional PBX. You should also note that, as with any PC-based solution, if your AltiWare server goes down, so will your VOIP service.

TouchWave WebSwitch 1608IP

If you are looking to get away from the PC-based architecture, you can implement a VOIP solution that replaces your PBX, such as the TouchWave WebSwitch 1608IP. If you do not already have a PBX, you can easily plug a solution such as the WebSwitch into your existing infrastructure. With a solution that acts as a PBX, either server-based or a switch, you have only one network to manage.

TouchWave is a new player in the PBX and VOIP market. Its WebSwitch 1608IP is a single-box solution with a full-feature PBX, voice mail system, auto attendant, and integrated VOIP gateway option. The WebSwitch is a good, scalable solution for linking multiple offices.

We began setting up ours by connecting two WebSwitches to our existing infrastructure, which included the two Windows NT servers designated as the San Francisco and New York branch offices.

After we got the two switches communicating, we installed SwitchLink, the WebSwitch Administrative software, which can be administered locally or remotely over the network. SwitchLink let us view WebSwitch configurations and add and configure more WebSwitches. TouchWave also provides desktop-control dialer software called PhoneLink with built-in Microsoft-Intel Telephony API (TAPI) 2.1 support, which allows end-users to make calls from Microsoft Outlook, Symantec Act, or any other TAPI-compatible software.

While using the TouchWave system, we encountered a little echo noise and delay. On a couple of occasions our connection was dropped. Nevertheless, TouchWave is a good VOIP solution for small to mid-size companies that want to optimise their branch office resources without breaking the bank. The WebSwitch is more scalable than the AltiGen solution.

VOIP on a bigger scale

If you have a large enterprise network or are responsible for an ISP's network, you will need a higher-end VOIP gateway solution than those we tried. A few vendors, including Lucent Technologies with PacketStar IP Gateway 1000 and VocalTec with Telephony Gateway Series 120, market their gateways only to ISPs. Higher-end solutions, such as Cisco's AS5300 with Voice Feature Card and Neura's Access Plus F200 Gateway, are more expensive but come loaded with robust utilities not found in the low-end and mid-range systems.

The management architectures are full-featured, with statistics, diagnostics, security, fax, and remote management capabilities. They are configured with the highest quality and the widest range of voice-compression technology. In addition, they provide bandwidth utilities and call-processing options, are scalable, and in some cases provide credit and debit card account software.

Unfortunately, these solutions are still an additional component on the network, as opposed to replacing current PBXes; you will save on long-distance calls, but you will still have to manage two networks.

Regardless of how you choose to add VOIP to your network, you will immediately begin to save on long-distance calls. You will reap both business and technical benefits, even though you will need to manage two networks -- at least until vendors can make the necessary hardware VOIP-compliant.

The bottom line

Voice over IP (VOIP) solutions

Summary: The recent release of several VOIP solutions finally make transporting voice over the Internet feasible. But until the technology matures, IT administrators must balance network management, voice quality, and reliability issues with existing infrastructures.

Business Case: With a VOIP gateway in place, a company can reduce its administrative costs by managing a converged network and save on long-distance calls routed through the Internet rather than the public switched telephone network, or PSTN.


+ Solutions let companies save on administrative and long-distance costs; sets up framework for advanced applications.


- Immature technology; hardware interoperability problems; voice transmission still subject to delay, jitter, and lost packets.

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