Fluke's LANMeter 675 can replace a shelf full of network-testing tools
Ben Smith
Something has caused a workstation to go down. Is it an application, the server, or the network? If it's the network, it may take a whole shelf-load of tools--load analyzers, protocol analyzers, cable testers, and traffic generators--to track down the problem. Or you can use the Fluke LANMeter, a veritable shop of networking tools that you can hold in one hand.
Fluke's LANMeter products provide you with just the network traffic information you need. To use it, you don't have to understand the low-level engineering of network communications or learn how to use a protocol analyzer. If your problems seem to be coming from a router, bridge, hub, or NIC (network interface card), you can plug the LANMeter directly into the su
spect device to test it. If the problem is not with the electronics, the LANMeter analyzes cables, too. Because it analyzes and tests protocols, networking hardware, and cables, this single tool can help you quickly isolate network problems.
With its backlit LCD graphics display and front-panel alphanumeric keyboard, the battery-powered LANMeter is a pleasure to use. A row of ``soft keys'' located below the LCD display take on the menu functions displayed along the bottom of the screen above, which makes it easy to navigate through the many LANMeter functions. More important, the 4 1/2-pound LANMeter is easy to carry around and connect to a network anywhere you go.
There are three LANMeter models to choose from. Fluke introduced the 670 Token Ring LANMeter ($6495) last year; the 672 Ethernet ($6495) and 675 Ethernet/Token Ring ($9495) models appeared this year. Models with screen backlighting cost $300 more. All prices include a case, an AC adapter, a wire-map/cable-ID remote adapter, and a util
ity disk.
I tested a 675 LANMeter for this review; I'll refer to it as simply the LANMeter hereafter. The three models differ externally only in the functions that they provide through the display and some of the connectors--depending on whether the particular unit supports Ethernet, Token Ring, or both.
Well-Mannered Statistics
Network-traffic analysis is the single most important tool in tracking down poor network performance. It's rarely necessary to see the contents of each packet for each protocol (the method a protocol analyzer uses), but it is important to find out which protocols are merely flowing and which are flooding.
Not only can the LANMeter display the distribution of network loads during normal operation, but it can also show you the source of error packets and, for Token Ring networks, perform soft error-domain analysis. Even when you are using the LANMeter for functions other than statistics, its multicolor LEDs display overall network load and errors.
On Et
hernet networks, the LANMeter's display of overall network statistics shows bandwidth utilization, collisions, errors, and broadcasts. The display shows the current and maximum percentage of each statistic in an active bar meter, next to a numeric display of the average and total for your sampling period. You can view the bar meter either as a logarithmic count or as a percentage of full load.
Another view shows error statistics, including, for Ethernet, jabber (illegally long frames), FCS (frame check sequence) errors, short frames, late collisions, remote collisions, local collisions, and ghosts (noise that might be mistaken for a frame). The display of these values consists of a pie chart with a count list. You can pursue many of the statistics to greater depth by pressing the zoom key on the front panel.
Two other network-monitoring views--protocol mix and collision analysis--provide you with similar displays, combining bar meters or pie charts with percentages or logarithmic counts. If you
experience traffic-load problems, three more statistics are of particular value to your problem analysis: the top senders, the top receivers, and the top sources for broadcasts (a common source of trouble in IPX networks).
When you use the LANMeter on a Token Ring network, the general network-statistics display gives you appropriate information for that area, including beacons, claim tokens, ring purges, broadcasts, and stations seen. The error-statistics display includes line errors, burst errors, receiver-congestion errors, frame-copied errors, lost token errors, and other soft errors. You can display fault-domain information for any error type, which shows both the error-reporting station and its nearest active upstream neighbor. Another display shows statistics on token-rotation time.
You can configure your LANMeter to log any of these statistics for time periods ranging from 24 minutes (at 1-second intervals) up to 5 days (at 5-minute intervals) and then download the table of statistics dir
ectly to a PC or over a modem. This is a valuable capability because it allows you to further analyze the data.
The only impediment to this process is the short 1- to 3-hour battery life of the LANMeter. Battery life depends on how much you use the display backlighting. You can, of course, leave the battery charger plugged in while you use the LANMeter. If the battery is fully charged, the charger continues to trickle power to the unit.
NICs, Hubs, and MAUs
The basic electronic devices of a LAN are the NICs in each workstation, the hubs and concentrators from which twisted-pair Ethernet LANs fan out, and MAUs (multistation access units), which are the Token Ring equivalents of hubs. Needless to say, these potential sources of trouble need to be identifiable and tested. For those purposes, the LANMeter provides a user-definable station list and a suite of tests.
The station-list database is another of the LANMeter's great conveniences. By default, each MAC (media access control) or E
thernet address is automatically associated with a default-station address that, if possible, is derived from the device on the network. Then, using the LANMeter's alphanumeric keyboard, you can add your own symbolic name.
The LANMeter is capable of maintaining 32 separate lists of 512 stations each. You can import or export the list to or from a PC, download NetWare and IP host tables, and even sort the lists. LANMeter uses the symbolic names in any reports that identify a station, including network-monitoring reports of top network users.
For each test, the LANMeter displays a diagram of how to connect it to the device or network for that particular test. Each test has a help screen describing the test. For example, the expert-T, NIC, and hub auto-tests display the following message: ``In the Expert-T test LANMeter checks the network Hub and the connecting NIC looking for any problems that could keep the NIC from successfully connecting to the network. If cabling problems are suspected, approp
riate cable tests will also be run.'' This explanation goes on for a few dozen screens.
The NIC test suite can discover the address of the device and test its link pulse, transmission sensing and generation, response speed, and phantom voltage, as well as check for duplicate addresses and lobe cabling (if appropriate). The final test is to let the LANMeter generate test network traffic. You can start by having it send PING (packet internet groper) packets to the devices and determine if they are alive and connected. Then you can have the LANMeter generate traffic loads while you monitor how the network handles it.
The Wire
If your network problems aren't in the applications or devices, they could just be in the wiring. There could be crossed pairs in the wiring closet, broken wires, bad terminators, or just one wire plugged into the wrong socket. The LANMeter can help you discover all of these problems.
Before you run any of the cable tests, you must tell the LANMeter what kind of c
able you are testing: 10Base-T category 3, 4, or 5; RG-58 (thin or foam thin); RG-8 (thick); Token Ring shielded twisted-pair (type 1, 2, 6, 8, or 9); or Token Ring unshielded twisted-pair (category 3, 4, or 5). Then you can test for cable length, distance to the largest fault, impedance, and DC continuity. For twisted-pair cabling, the LANMeter checks the transmit and receive pairs and detects split pairs occurring at the connector.
By attaching identifier dongles (which are optional) to the ends of twisted-pair cables, you can give each cable a separate identifier with which the LANMeter can generate a logical wiring map from the closet. This is a far cry from wire testing with two technicians, a Multimeter, and walkie-talkies. Thanks to the LANMeter, a technician working alone can be far more productive in figuring out a wiring closet.
Solving TCP/IP and NetWare Problems
The LANMeter lets you analyze TCP/IP or NetWare activity separately from all other activity on mixed-protocol LANs. T
he LANMeter logs information on ICMP (Internet Control and Message Protocol) packets that tell of unreached destinations, redirection, source quenching, exceeded delivery time, parameter problems, and echo requests and replies (i.e., PINGs). For any of these statistics, you can zoom in to see who the top senders and receivers are and to whom they are talking.
While there are plenty of TCP/IP network problems that you can identify with the LANMeter, there are also special NetWare IPX/SPX problems for which the LANMeter is unusually well suited. For instance, the LANMeter can identify all visible NetWare servers. Then if you know which workstations are running on NetWare, you can send a NetWare PING to see if a server or workstation is available from the LANMeter's location.
The NetWare-specific statistics collection separates total IPX activity into file activity (i.e., delays, file, and print) and packet activity (i.e., delays, routed packets, and burst packets). Then you can also do a routing a
nalysis that displays local-to-local, local-to-remote, and remote-to-local activity in a pie chart. As with most LANMeter statistics, you can drill down with all NetWare tests and see more detailed statistics on the top local-traffic nodes. Using the NetWare menus, you can also see the top senders and receivers of NetWare activity only.
Fishing Expeditions
Within my first hour of using the LANMeter, I successfully identified a network printer that was unnecessarily loading the BYTE network with broadcast error messages, and I narrowed an intermittent problem to in-the-wall wiring between BYTE's editorial offices and the BYTE Lab. It's that easy to use.
The LANMeter is also strong in performing routine analysis. You can set it up in a wiring closet and let it collect data on the subject of your interest for a day or so and then send the data to a computer for further analysis. You can also send all the data and screens to an internal print spooler that will relay the information to a printe
r when you've returned from your data-collection expedition.
There is little that I can criticize the LANMeter for. The price is high and the battery life is short, but when you consider the functionality and ease of learning that characterize this attractive instrument, its convenience far outweighs its cost. The LANMeter is certainly less expensive, more portable, and easier to set up than the array of instruments it replaces.
Indeed, there is much to praise the LANMeter for. Its manual is exceptionally well written, giving instruction in not only how to operate the LANMeter but also how to use it to find different kinds of problems and what might be causing them; it even offers some solutions. But the greatest praise goes to the LANMeter's designers, who knew what the major tools for network diagnostics are and how to organize them all into one solid, compact unit.
The Facts
Fluke 675 LANMeter $9795
(for Token Ring and Ethernet, with backlighting)
Fluke Co
rp.
P.O. Box 9090
Everett, WA 98206
(800) 443-5853
(206) 347-5500
fax: (206) 356-5116
Photograph: Fluke crams a useful mix of LAN-testing functions into the LANMeter's rugged 4 1/2-pound, 11 1/2- by 6 1/2- by 2 1/5-inch package. Batteries last up to 3 hours if you don't use the screen backlighting. Five keys located below the LCD display take on the functions displayed on the screen above (inset).
Ben Smith is a consultant, a former BYTE Lab testing editor, and the author of Unix Step-by-Step (Hayden Books, 1990). You can reach him on the Internet at
ben@ronin.com
or on BIX as ``bensmith.''
Network Problem Solver
