February 29, 2008
By Ted Stevenson
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."
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| 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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