Giving Voice the Bandwidth it Needs

By Ted Stevenson

February 29, 2008

High-quality VoIP requires network priority. Now there's a tool that guarantees it.

Propel Software this week launched a product that solves a problem most people don't know they have: performance degradation of time-critical networked applications due to competition for bandwidth.

The solution? Propel Personal Bandwidth Manager.

Why do people need it? According to Propel CEO David Murray, it's because, on the one hand, "there are more and more applications that people are using on their networks that are time-sensitive," and on the other, "there are more and more applications running on the PC that are using the network as if they own it—often outside of the control of the user."

The result of this mix? PC-based voice over IP applications, conferencing applications, collaboration applications, interactive games, and the like—all of which need high throughput and low latency—that can perform poorly and unpredictably.

Murry pointed out that there is a range of scenarios in terms of the degree of control the PC user can exercise over possible bandwidth competition. In an obvious example, when you're making a VoIP call, you probably wouldn't simultaneously initiate an application download off the Internet. But other scenarios are subtler.

"You might be trying to do something that's important and time-critical," Murray said, "and your PC decides that it's time to download some update software in the background. For example, Adobe likes to download new versions of Acrobat whenever it feels like it."

Then again, "you might be in the middle of a long file upload when you have to take a Skype call," he pointed out.

And it is uploads, rather than downloads that are apt to create serious performance issues. That's because most people's residential Internet connectivity is asymmetrical: "Upload links tend to be much slower than download links," Murray said—sometimes by a factor of ten or more—"and these time-critical applications are typically exercising the upward link as a key part of their job."


PBM Traffic Monitor
Figure 1—Click to see full-size image

So, developers at Propel created Personal Bandwidth Manager to address the three bandwidth-related issues that PC users face: knowing what's going on on the network (i.e., what applications are using the network) at any point in time; knowing how much bandwidth they're consuming over time; and—the key point here—managing how different applications compete to use the network, especially in the upward direction .

Network activity and cumulative bandwidth use are tracked by the PBM Traffic Monitor (see Figure 1), a dynamic GUI that displays these numbers in real time. Competition management, however, happens out of sight—and, for this version, at least, out of the user's control.

"Propel PBM manages competition automatically, giving higher priority to the more time-critical applications," Murray explained. "Our theory about that is that you just want it to work. We wanted to be sure we got the basic model right—that the automatic feature was there—and see if we can get mainstream users to adopt that."

While he acknowledged that some degree of user override might be a useful feature to add to a later version, Murray told VoIPplanet.com "Configuring all that stuff and keeping it up to date is not the sort of thing that your average user wants to do—or is even trained sufficiently to do."

"All that stuff" includes numerous port settings, figuring allocation percentages, reading headers, and adapting to changing application behaviors, as programs update themselves. And then there's the fact that some applications—Skype is a prime example—can generate multiple types of traffic: voice, video, IM, file transfers, etc. "This is complex stuff," Murray said, and indeed, part of the offering is regular traffic-shaping policy updates that adapt to the constantly evolving application requirements.

With PBM on the job, PC users simply won't have to worry about bandwidth competition. When a time-sensitive application becomes active on the network—whether planned or unplanned, it gets the bandwidth it needs.

Murray drew the hypothetical case of a Web designer "stuck between a rock and a hard place"—needing to upload some last-minute site updates and, at the same time needing to call the customer for whom the work is being delivered.

With Personal Bandwidth Manager, "before you launched the call—when there was no competition going on—the file upload would proceed at full speed. But when you initiate the call, the software would recognize that a call was going on, make sure Skype was getting the bandwidth it needed, and allow the file transfer to continue in the background with whatever bandwidth was left over—without impacting the call quality."

It seems likely that a sizable community of sophisticated PC professionals (not to mention avid gamers) will benefit from this utility. A license will eventually cost them $29.95, but those taking advantage of the current introductory offer will pay $19.95.



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