hen your network is sick, you become the network doctor. One tool in your "little black bag" of diagnostic tools should be a handheld network analyzer. These devices can reveal cable faults, detect chattering network adapters, identify switch malfunctions and determine the nature of a router malady. These are the problems that cause most network infrastructure failures. Having the right network testing tools can save hours or even days of network downtime.
When trouble strikes, you'll want to be ready to quickly diagnose the problem.
Protocol analyzer software on a notebook computer can be helpful when you're trying to diagnose a network problem, but a protocol analyzer can't tell you whether a cable contains a broken wire, some insulation has chafed from a cable or a sick network adapter is behaving strangely (You can brush up on your cable testing terms and concepts, go online to www.nwfusion.com, DocFinder: 1024).
Handheld network-testing device vendors have included several protocol-analysis functions inside what were formerly just cable-testing tools. The vendors say the tools can quickly spot problems ranging from cable faults to overutilization. To test these claims, we invited vendors to submit handheld devices to our lab for evaluation. We looked for fast, accurate determination of cabling and other network problems; some ability to transfer data into a PC for further analysis and reporting; ease of use; and a reasonable price. We particularly wanted a device to be able to diagnose problems on a live network, not just at cable installation time.
Agilent Technologies submitted FrameScope 350 Network Performance Analyzer kit, which includes FrameScope 350 and DualRemote 350. Psiber Data Systems shipped us its Pinger Network IP Test Tool. Fluke Corp. sent us three tools, NetTool Connectivity Tester, OptiView Network Analyzer and OneTouch Series II Network Assistant. Because Fluke recently acquired another handheld testing-tool vendor, Microtest, we let Fluke submit three products for this review. Ideal Industries declined to send its Lantek 7, saying the device is just for checking new cable installations.
In selecting a winner, we discovered that two of the five products were worthy of a World Class Award. Fluke's NetTool gets the official World Class nod because it accurately pinpointed cabling and network faults with aplomb, and without a fancy color display or extra bells and whistles.
Pricing differences
Fluke's NetTool ($900) offers a basic set of essential features for detecting problems such as cable faults, link configuration errors, odd network adapter behaviors, network health ailments and unresponsive servers. Although the NetTool's user interface and results display are simple and utilitarian, it has almost as many diagnostic features as Agilent's FrameScope 350 ($6,000) and the OneTouch Series II Network Assistant ($4,200) for a fraction of the price. Both the FrameScope 350 (2.6 pounds) and the OneTouch (1.7 pounds) are heavier touch-screen cable fault and network-diagnostic tools, while NetTool is a lightweight five-key LCD-screen unit. The Psiber Pinger ($350) is an 8.7-ounce, easy-to-carry, 19-key device that pings from one to eight IP addresses via Internet Control Messaging Protocol (ICMP) packets.
Fluke's OptiView Network Analyzer ($13,000), the heaviest device at 6.2 pounds, is the ultimate network-diagnostic tool. It's a full-blown touch-screen protocol analyzer outfitted with comprehensive cable-testing capabilities.
Physical features
The simple but utilitarian NetTool has four cursor buttons, a select button and a power button. Getting used to touching the buttons with just the right amount of pressure takes some practice. The screen is a simple eight-line monochrome LCD with rudimentary but easily recognizable icons for network devices and basic operations such as navigating the different screens. The user interface is practical, straightforward and surprisingly intuitive. The initial screen offers two choices: autotest and device configuration. Selecting autotest when the unit is attached to a cable with a wiremap plug at the other end invokes the NetTool's cable-testing functions. Choosing autotest when the unit is attached to a hub or switch displays network health, link configuration and other network-diagnostic test results. If you connect a network device to one of NetTool's two RJ-45 ports and connect the other RJ-45 port to that device's network cable, autotest collects and shows identifying information and traffic statistics for the network device.
The OneTouch sports a monochrome touch screen. Fluke doesn't supply a stylus with the OneTouch, but we didn't need one. Fingertips worked just as well on the well-spaced icons that Fluke designed. The display updates continuously, and touching a screen navigation icon, device icon, IP address or other on-screen element lets you quickly drill down to see more detail or to perform a specific operation.
The FrameScope has a beautiful, color LCD touch screen that is a dream to operate with or without the supplied stylus. The DualRemote 350 is a slave unit that needs no user interaction, but it has 16 LEDs that display cable-testing results such as attenuation errors, split pairs, NEXT errors, return loss errors and ELFEXT errors. The FrameScope's screens are not quite as intuitive as those of the OneTouch, but only a few moments are needed to get used to them each time the machine is powered on and to go searching for trouble on the network. Unfortunately, FrameScope doesn't use its list of discovered nodes to establish a default collection of network devices to test. You must manually add devices to a particular autotest suite.
Imagine a color notebook computer running Windows. Now take away the keyboard and give the computer a touch-screen display with a well-designed, easy-to-navigate icon-based user interface. Install protocol-analysis software on the computer and a network interface that can run cable fault diagnostics and measurements. Voila! You've created an OptiView Network Analyzer. OptiView's user interface will be instantly second nature to anyone familiar with Windows who can use a stylus to select on-screen icons, buttons and data elements. OptiView's user interface has an on-screen virtual keyboard, but you can optionally connect a standard PC keyboard to an OptiView.
The Pinger has 19 keys that resemble a telephone keypad with extra functions. Just like telephone keypad keys, twelve of the keys are for data entry of names and IP addresses. Four are cursor keys, and the remaining three are function keys for selecting on-screen menu items such as exit, save and setup. The four-line monochrome LCD screen is a bit wider than a typical cell phone's screen. Navigating the Pinger's few screens is a breeze.
All the units come with batteries and AC adapters, and, to conserve battery power, they all go to sleep or shut down after about 5 minutes of inattention.
Fluke's NetTool
The NetTool can run cable tests to determine problems such as cable length and whether a wire is broken. Attaching the supplied wiremap adapter to the far end of a cable lets you see whether the cable is wired correctly. NetTool also can show whether a network is using Token Ring or Ethernet, and can also detect a telephone company connection by displaying which pins are carrying tip and ring signals.
Inserting a NetTool between a network device and its hub or switch (it includes two RJ-45 ports) provides a lot of useful information about the device and its network connection. The device also can display the network device's name and IP, IPX and media access control addresses, along with the identity of servers and router gateways the device talks to.
NetTool has only one testing function, labeled autotest. Selecting it gave us a display showing detected problems, recognized protocols, and identified key devices and general network health. On a separate menu screen, NetTool offers a speedometer-style network utilization display and the ability to ping IP addresses.
Fluke's OneTouch Series II
Even more versatile than the NetTool, Fluke's OneTouch Series II Network Assistant is everything a handheld cable and network-testing device should be. Only its high price kept it from the top spot.
The cable-test mode included similar cable tests of the NetTool, but it also lets users enter custom Nominal Velocity of Propagation (NVP) values to test cables other than Category 5/6E. It also has an xDSL option for testing DSL connections.
The OneTouch network diagnostics are comprehensive. The autotest function discovers network devices and displays the result as icon-associated counts. Touching an icon brings up multiple levels of considerable detailed information.
Like the NetTool, OneTouch recognizes protocols to identify devices as IP servers, routers or other devices. Also like the NetTool, OneTouch has two RJ-45 ports, so the unit can be inserted between a network device and its network connection. The OneTouch can ping devices via ICMP packets, trace routes to devices and query devices via SNMP.
Agilent's FrameScope
Agilent's FrameScope initially enters cable-test mode and shows the length of the cable it's connected to, among other tests. It also can let you modify details such as wire pairings for Category 5E and 6, but not NVP values. FrameScope's cable certification tests require the DualRemote 350 option, a $2,000 separate unit connected to the other end of a cable.
Touching the network icon switches the FrameScope to network test mode. In this mode, FrameScope offers a plethora of diagnostic functions. In contrast to NetTool's single autotest function, FrameScope can have multiple autotest suites. Each suite represents a collection of one or more network devices you want to test. Each time a test is run, you can specify which suite to use, the number of times to iterate the test and the number of minutes to pause between iterations. The FrameScope displays network utilization and frame (by unicast, broadcast, multicast and error categories) counts and percentages along with protocol (by IP, IPX and other categories) counts and percentages.
FrameScope's station list shows each device's IP address and DNS name for the stations, servers, routers and remote stations it discovers on the network. Selecting a network device from the list reveals details about that device, such as frame counts and percentages categorized by type of frame - unicast, broadcast, multicast and error.
Fluke's OptiView Network Analyzer
If your company can afford it, Fluke's OptiView Network Analyzer is the ultimate cable-testing and network-diagnostic tool. The OptiView's cable-testing feature had basic tests, including cable length, wiremap information, short circuits and the like. The Ethernet Pro Gigabit model can check 10/100M bit/sec and Gigabit Ethernet nets.
The OptiView's network diagnostics rival those of a full-blown protocol analyzer. It shows multiple port switch statistics on one screen, which lets you compare switch port traffic levels at a glance. The multiport router display is similarly useful. The OptiView graphically reveals network utilization details, device discovery, network discovery, protocol statistics, problem discovery and recognized events. The device also can generate traffic, map topology and capture and decode packets.
Psiber Pinger Network IP Test Tool
Psiber's Pinger Network IP Test Tool is a simple device with a single purpose. It emits ICMP "ping" packets to test IP connectivity to one to eight network devices. The Pinger displays the success or failure of the operation, the round-trip time for the packets and an indication of whether the contents of the received packets match the contents of the transmitted packets or whether the packets were damaged in transit.
Odds and ends
Except for the Pinger, all the units we tested can transfer test results into a PC via a serial link. In each case, getting the transferred data into a spreadsheet or database for further analysis and reporting is completely painless.
The NetTool's documentation consists of a user guide and quick-reference card, while the OneTouch comes with a user guide, "getting started" guide and a quick-reference card. Both sets of documentation were more than adequate.
Because the FrameScope is a relatively new product, its user manual was a preliminary draft and we noted a few glaring errors. For example, the manual said the FrameScope automatically polls your network and discovers devices when you power it on. We found that the unit powered up in cable test mode. The OptiView comes with a user guide and quick-reference "at a glance" card. The user guide is brief and doesn't discuss OptiView's many features with as much depth as we would have liked. The Pinger's documentation is an eight-page card-stock booklet that contains essential information but lacks a professional appearance.
Conclusion
Dropped packets, cable faults, failed network adapters, misconfigured devices and sluggish performance are client session killers. A tool that can reveal cable faults and network health is an essential requirement in any network administrator's first-aid kit. We recommend budget-conscious administrators take a close look at Fluke's NetTool. However, for those with lots of bucks to spend on diagnostic tools, we suggest the OneTouch unit.
Nance, a software developer and consultant for 29 years, is the author of Introduction to Networking, 4th Edition and Client/Server LAN Programming. He can be reached at barryn@erols.com
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