Be Impulsive

Keeping a finger on the pulse of numerous enterprise applications and network links can raise the blood pressure of even the fittest network manager. Trying to diagnose network anomalies and pinpoint problem areas when all you have to work with are statements such as “the network is slow” can be an exercise in frustration. Having real-time and historical statistics on packet loss and latency across the enterprise would be a lifesaver.

Front end the statistics with a snappy graphical interface and you would have a winning combination. And that’s what Visualware Inc. has delivered in VisualPulse 1.7: a winning combination of statistics and graphical interface that should be in every network manager’s bag of tricks. VisualPulse has taken the place of our home-brewed diagnostic tools because it is easier to use and more powerful than the tools we had cobbled together. A less expensive, but more limited, tool we have used is Nessoft’s PingPlotter. We liked PingPlotter, but it doesn’t offer the ability to monitor multiple sites, or have a Web-based interface like VisualPulse’s, which let us use VisualPulse from anywhere.

VisualPulse 1.7 is a network-monitoring tool that provides network managers with detailed statistics on packet loss and latency. VisualPulse sends Internet Control Message Protocol (ICMP) ping packets at regular intervals and measures packet loss and round-trip time. While this technique works well in most cases, it doesn’t work in every instance. Many sites block ICMP packets, thus preventing VisualPulse from reaching its intended destination. We found this to be only a minor inconvenience.

VisualPulse is Web server-based and operates on Linux and Windows platforms. While VisualPulse supports Windows 95, 98 and Millennium Edition, Visualware recommends deploying VisualPulse on a Windows 2000 server in an enterprise environment.

A feature of VisualPulse that we found particularly attractive was its minimal client requirements. If you have a Java-enabled browser you can access all of the reporting and configuration options of VisualPulse. VisualPulse requires Microsoft Corp.’s Java VM build 5.00.3167 or later, and the use of Internet Explorer is recommended.

VisualPulse 1.7 earns our World Class award for its ability to monitor packet loss and latency, its e-mail notification features, snappy graphical interface, ease of installation and rock-solid stability.

Watching the Wires

We’re big believers in putting reviewed products to the ultimate test: deployment in a production environment. Tests in a controlled laboratory environment are fine, but we’ve found that some products behave differently when subjected to the chaos of a 30,000-node enterprise network.

Shortly after we received our copy of VisualPulse our network crew was summoned to diagnose intermittent application slowdowns at an off-campus location. The site was connected to the campus through a 10Mbps Ethernet over an ATM metropolitan-area network. Users at the remote site complained of application timeouts, dropped sessions and network sluggishness. The users blamed the network and the service provider blamed the users.

We installed VisualPulse on a RedHat 7.2 Linux platform located on our backbone and configured it to monitor multiple devices on the off-campus network. After several days of testing we used the historical reporting features of VisualPulse to conclusively demonstrate to the users that the LAN and the WAN link were performing perfectly. It’s hard to argue with a graph that shows a 0 per cent dropped packet count and a latency of less than 20msec. The problem was the configuration settings on the application server. Without the statistics provided by VisualPulse, we could easily have spent several weeks in “finger-pointing” mode.

Serving Up Statistics

The VisualPulse home page is extremely well laid out. All the functions needed to configure and operate VisualPulse are grouped into status, report and tool headings. The status group is the heart of VisualPulse, containing links to a listing of all systems being monitored, critical latency and packet loss reports, and the system monitor.

The system-monitor page provides a scrolling display of the response time and packet loss for each system VisualPulse is watching. If less than five packets have been lost, the host name is highlighted in yellow. If more than five packets are lost it turns red. Packet loss is indicated by a vertical red bar, and latency by a vertical black bar. This page was so well laid out that we could glance at it and get an immediate sense of network health.

Clicking on a host listed on the system monitor page brings up a real-time graphical display of latency and packet loss. Historical statistics are accessible from the same screen choosing a time interval of last hour, last day, last week or last month.

VisualPulse provides a simple-to-use e-mail notification feature that we really liked. Plug in your mail server host name and the e-mail address you want alerts sent to and you’re ready. And don’t worry about using long-winded status reports on your pager. Check the “suppress headers” and “suppress duplicates” boxes and VisualPulse limits message contents to the most important details.

With the number of bad guys hacking away on the Internet, network managers might be nervous about putting a list of critical systems and network performance statistics where everyone can see it. Don’t worry – VisualPulse gives administrators a robust set of security options to keep the black hats from gaining access to vital network statistics. Administrators can define IP address-based access lists by using a combination of access verbs and network addresses. There are three access verbs: deny, full and super. “Deny” prevents the listed IP address from any access to VisualPulse. “Full” lets users access all features, and “super” gives full access and the ability to connect even when the maximum number of concurrent users has been exceeded.

Installation and Documentation

The installation process was simple and well documented, and we didn’t encounter any problems. We also installed an X Window virtual frame buffer that VisualPulse needs to run in the background as a daemon process.

The documentation for VisualPulse is excellent. Visualware provides an on-line frequently asked questions and user’s manual that is well written and superbly illustrated with screenshots. We easily found answers to all our questions and didn’t have to call technical support.

VisualPulse’s combination of functionality, reliability and low cost earn it our World Class award and make it a definite “must have” for an enterprise network manager.

At press time Visualware announced the release of VisualPulse.

Bob Currier is the ECI director of data and telecommunications at Duke University in Durham, N.C., and the 1998 grand-prize winner in the Excellence in Campus Networking competition sponsored by CAUSE, a user group for computer professionals in higher education. He can be reached