October 1999

[TARANTELLA]   [TELEGRA VQT (Voice Quality Tester)]

TARANTELLA
SCO (The Santa Cruz Operation)
SCO Offices
Encinal Street
Santa Cruz, CA 95060
P: 831-425-7222
Web: www.sco.com 

As developers and systems integrators are probably all too aware, everyone wants to get their applications on the Web these days. Whether you run a call center, are an application service provider, or just maintain VPNs for an enterprise, the ability to bring your applications onto the Web and to access these applications through standard, familiar interface represents a significant potential savings in cost, time, and system resource utilization. The big questions are: How do you do it, and how costly will the process be in terms of both time and money?
SCO would like to answer those questions for you, and the answer involves their new application broker product, Tarantella. If you are interested in an easy way to Web-enable your applications, you might want to stick around and listen to what SCO has to say.

SOME WORDS ON UNIX
First of all, Tarantella is brought to you by the same people who bring you UnixWare and UnixWare 7.1, two of the most powerful and reliable operating systems around for network computing and business application development. But you’re not a Unix-based shop? No problem. While Tarantella runs on a Unix server, it also interacts with existing mainframe, Windows, and Unix applications and can support any client type, including Windows PCs, Palm computers, and Java-based network computers and kiosks.

And don’t be too quick to dismiss this Unix-based network computing model and its role in CTI. Gary Marks, vice president of marketing for Dialogic, stresses the importance of Unix in computer-telephony development: “Dialogic’s customers continue to demand enhanced support for Unix system platforms. Establishing UnixWare 7 as a standard Unix system for Intel platforms was an easy choice for us.”

SO HOW DOES IT WORK?
The Tarantella application broker is a software layer that sits between the application (running on its original server) and the Java-enabled Internet device (the Java client). Instead of requiring the client to support the emulation software that might be needed to access various applications running on a mainframe, Unix, Windows, or X Windows servers, Tarantella handles the emulation and delivers it to the client computers as Java applets. In effect, Tarantella acts like a piece of CTI middleware.

But Tarantella has more intelligence than traditional middleware. For example, Tarantella employs Adaptive Internet Protocol (AIP) to suit the information sent to the specific network and client characteristics. This means that if you are stuck using a low-bandwidth connection, AIP only sends compressed, completed display refreshes across the network. Emulation processing takes place on the server, so that remote users are able to receive information at speeds similar to what they would expect if they were working with a direct connection to the LAN. This is a “self-tuning” process requiring no intervention or management by the system administrator.

Additionally, Tarantella supports SSL and RSA cryptographic services, allowing for secure, authenticated access to your services.

These features make Tarantella a particularly helpful tool for Application Service Providers (ASPs) who can market existing applications to outside organizations without requiring any updating or rewriting of the code — even if the application was developed before the demand for “Internet-enabled anything.” Tarantella also simplifies the process of Web-enabling a call center by using a network computing model rather than the Windows client/server model. It allows for centralized administration and a single GUI (SCO calls this the “webtop”) interface for all applications, regardless of the server they are running on.

Not only does this model simplify the process of Web-enabling your applications, it also reduces the estimated TCO for an organization when compared with the traditional client/server model.

Tarantella supports all major versions of Unix, including UnixWare and UnixWare 7, AIX, HP-UX, Sun’s SPARC Solaris, and Siemens’ Reliant Unix. SCO also recently announced Tarantella is available on Compaq’s Tru64 Unix platform. And while Tarantella does not currently run on Linux, SCO assures me that they are keeping an on the Linux market so they could “respond with a Tarantella port to Linux if and when the market is ready.”

Tarantella is currently priced at $395 per concurrent user. For more information or to download Tarantella directly, please visit http://tarantella.sco.com

TELEGRA VQT (Voice Quality Tester)
Hewlett-Packard Company
5070 Centennial Boulevard
Colorado Springs, CO 80919
P: 800-452-4844
Web: www.hp.com 

With the circuit-switched PSTN, voice quality has long been pretty much a given, especially on local and intra-national calls. Delay and echo might become problems with international calls, but for the most part even these are remarkably clear and reliable. Of course, this is the result of some intense behind-the-scenes work by carriers and service providers, but to some extent it has also been a result of the nature of the network itself.

With 64 Kbps voice being sent over an established circuit connection, voice quality testing is a relatively straightforward process of comparing an initial waveform input to a received waveform output. This is not to imply that voice quality on the PSTN is a simple matter, but the pathway that the voice travels remains fairly consistent and the waveform on the receiving end can be compared directly to the waveform on the initiating end using an oscilloscope.

With a packet-based network, this isn’t the case. Packets traveling a network act differently from circuit-switched waveforms. Packets can get dropped out of the stream, depending on the available bandwidth and the discard policies of the relevant gateways, and they don’t all take the same route to the endpoint. What this meant is that testing voice quality in a packet-based network is more than just a matter of comparing scope readouts.

That is why the newest addition to Hewlett-Packard’s Telegra line of testing products is the Telegra VQT or Voice Quality Tester — a tool for testing end-to-end voice quality over packet-based networks. Until now, testing voice quality of IP networks involved a fairly subjective process where a group of listeners judge the quality of various samples on a scale of 1–5. The resulting data (referred to as the MOS, or mean opinion score) provides some idea of the quality of the network for voice calls.

The Telegra VQT provides a more objective assessment of voice quality, based on the use of PSQM+ (an improved version of P.861). PSQM+ (Perceptual Speech Quality Measurement plus) is a standard designed for use on packet-based networks and allowing measurement of such elements as severe distortions and time clipping.

Telegra VQT behaves on the network like a telephone: it generates a call, then sends speech samples over the network to the receiving end, where these samples are recorded and compared to the originals. Additionally, the VQT can take a “snapshot” of existing network conditions and then replicate these conditions back in the lab to provide a precise accounting of how voice will impact the network. Changes in the network design or traffic load can also be simulated to see how these changes affect voice quality.

As with any new technology, one of the biggest challenges of actually implementing VoIP is finding the people with the knowledge to support and design VoIP networks. Stefan Pracht, product marketing manager of HP’s Network Systems Test Division, said that this is especially true of testing voice quality in VoIP networks — no one has really had to do this before, and therefore the skills required are not easily found.

With this in mind, Stefan said that HP had designed the VQT to compensate to some extent for the scarcity of skilled personnel. Its visual drag-and-drop GUI makes it relatively easy for a novice without previous voice quality experience to use, providing information in graphical as well as tabular formats, and including a task list of graphical scripting tools.

But the VQT also provides significant drill-down functionality, allowing an expert user to change various setting and parameters — obtaining the full value from the tool. With such functionality, specific network components that are negatively affecting voice quality can be identified.

Finally, the Telegra VQT can be accessed remotely using software such as Symantec’s PCAnywhere. When combined with the familiar GUI this capability can be useful for providing expert diagnosis only where needed. Several field technicians might use the devices locally to test network conditions and perform initial diagnosis, and when a more serious problem or issue arises, the resident expert can dial in and take control of the machine directly from a laptop.

With the Telegra VQT you need fewer voice quality experts to maintain your network, and those you do have are made more effective. This means your VoIP network can be up and running (earning and saving you money) while you rest assured that your voice quality is as good as that of the PSTN or any other benchmark you establish.