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November 2008 | Volume 11/ Number 11
Editorial Series Sponsorship

ClearSight Enhances its Visual Troubleshooting and Analysis Solution with Time Synchronization

By: Richard “Zippy” Grigonis

In our August 2008 issue, Yours Truly examined ClearSight Networks ( and its ClearSight Network Time Machine® (NTM) — a multiuser, turnkey recorder appliance for Fortune 1000 companies that leaves ordinary network protocol analyzers in the dust. Teamed with its Atlas, a processing engine that can index, categorize and make sense of terabytes of network data and applications without resorting to complicated packet decodes, superlative data mining and analysis — even on voice-related traffic — can be performed and stored in a powerful relational database.

Recently ClearSight has added a remarkable new feature to the NTM, at no additional costs. Available now on the NTM, it bears the low-key moniker, “Support of Network Time Protocol (NTP) Servers”. Don’t let that verbiage fool you — it’s one of the more amazingly useful new features in the whole package, as we shall see, and it’s what separates ClearSight from the host of companies that provide network tools and solutions

To set the stage, understand that, in order to find bottlenecks and other problems in a network, ClearSight’s NTM calls upon “analyzers” or probes that are placed at various locations and which capture traffic simultaneously. As it happens, ClearSight technology has multi-segment analysis capabilities — data collected from multiple network segments can be analyzed as the traffic flows from one segment to the other, so you can accurately visualize how packet transactions move end-to-end even through a complex network.

Steve Wong, ClearSight’s Vice President of Marketing, says, “We can follow VoIP packets as they go from one end of the network to the other, giving you enhanced visibility across your networks. It’s very difficult, if not impossible, to do that with a traditional analyzer, because they are typically deployed at one point in the network, and so you can only see that packet as it travels through that segment. When you couple that with our ladder view charts, you can get a complete picture of protocol interactions across multiple network elements.”

In the past, however, one “fly in the ointment” when it came to real-time analysis of networks and network applications was the fact that vendors’ probes would not “synch-up” properly — there could be slight differences in the internal clocks of each probe. When you install a number of probes on your network and the clocks aren’t in sync, troubleshooting analysis becomes much more difficult — even impossible. You can run into a situation where a frame mistakenly appears to arrive at one segment later than it actually did, simply because a probe’s timing isn’t correct. Worse, you could be spending time and effort analyzing a problem that may not even be there.

That’s where the new NTM feature comes into play.

“One way we have addressed this timing issue is in our new release of our NTM software which supports NTP [Network Time Protocol] servers” says Wong. “Now, using NTP, all of your Network Time Machine probes can be synched-up and correlated and you’ll be able to do multi-segment analysis in a much more effective way.”

Wong elaborates, “Once all of the probes are in-synch, you can now genuinely measure latency, since two probes are looking at two different points, and as a packet moves from one probe to the other — say New York to London — the transfer time is measured using what appears to be the same clock. You can achieve latency measurement accuracy down to the millisecond. It’s even possible to improve the granularity further and attain nanosecond timing resolutions, if you decide to add GPS capabilities to the NTM probes with another solution from ClearSight called Cronos. With voice traffic and time-critical media technologies, such accurate latency measurements are critical. The combination of VoIP visual analysis and high precision latency measurements make for a truly unique solution.”

“By coupling this probe timing synchronization capability with our analyzer’s multi-segment analysis capabilities, you can now correlate highly accurate data collected from multiple network segments,” says Wong. “You can now carefully examine the endpoint connections and see how the transactions propagate through our multi-segment ladder charts, and you can get a precise timestamping of the voice packets as they move through the network. Not only does this enable you to find bottlenecks, it actually allows you to characterize and measure them more accurately than ever before. And of course, all our solutions have voice content reconstruction and playback capabilities.”

ClearSight has once again boosted its technology to a new level. Customers currently using the Network Time Machine to better troubleshoot their networks can now perform analysis and monitoring of the network at an unprecedented degree of accuracy. IT

Richard Grigonis is Executive Editor of TMC (News - Alert)’s IP Communications Group.

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