Abstract

How Accurate Is Your LAN Analyzer?

This January 1994 Data Communications lab test, conducted by Kevin Tolly of Interlab and David Newman of Data Communications, evaluated the accuracy and practical usefulness of LAN analyzers and frame generators. The article focused on a critical network-management question: when administrators rely on analyzers to diagnose congestion, protocol problems, frame errors, and utilization levels, how accurately do those tools capture, decode, count, monitor, and generate traffic?

The lab examined a broad range of products across four categories: software-based analyzers, midrange analyzers, high-end analyzers, and frame generators. Products tested included analyzers from Azure Technologies, Protocols Inc., Triticom, Hewlett-Packard, Network General, IBM, Siemens Industrial Automation, Tekelec, and Wandel & Goltermann, plus frame-generation products from Alantec, LANquest Labs, and Netcom Systems. The test covered Ethernet, token ring, and FDDI environments, depending on product support.

The results showed that LAN analyzer accuracy varied significantly by product, topology, traffic type, and task. The article emphasized that analyzers were expected to perform several distinct jobs: monitor live traffic, capture and decode frames, identify protocol activity, report errors, filter traffic, generate frames, and present results in a way that network managers could use. No single product excelled in every area, and the lab found that some tools were strong monitors but weaker frame generators, while others were better suited to protocol decoding, long-term troubleshooting, or high-speed environments.

Azure Technologies’ LANpharaoh received a Data Communications “Tester’s Choice” designation in the software-based analyzer category. The article praised its ability to capture Ethernet traffic, decode a wide range of protocols, and provide useful software-based analysis at a comparatively low cost. Hewlett-Packard’s Network Advisor also received a “Tester’s Choice” designation. The lab highlighted HP’s strong all-around monitoring and analysis capabilities, broad protocol-decoding support, predefined filters, and practical features for enterprise troubleshooting.

Among the high-end products, IBM’s Dataglance, Siemens’ Protocol Tester K1100, Tekelec’s Chameleon 100, and Wandel & Goltermann’s DA-30 offered more specialized or advanced capabilities, particularly for FDDI, token ring, and multiprotocol analysis. Network General’s Expert Sniffer remained an important midrange analyzer for complex network analysis, while HP’s Network Advisor stood out for its balance of performance, usability, and enterprise-oriented functions.

The test also showed that frame generation was difficult to execute accurately. Products such as Alantec’s Powerbits, LANquest Labs’ Framethrower, and Netcom’s ET-1000 were evaluated for their ability to generate traffic at defined rates and frame sizes, but the lab found that practical performance could vary depending on topology and traffic pattern. The ability to generate repeatable test traffic was important because inaccurate frame generation could compromise benchmarking and troubleshooting work.

Overall, the article concluded that LAN analyzers were indispensable but not interchangeable. Network managers needed to choose products based on the specific environment they supported, including Ethernet, token ring, FDDI, protocol mix, traffic volume, and the depth of decoding required. The most useful analyzers combined accurate monitoring, strong protocol decoding, flexible filtering, clear reporting, and reliable capture behavior under load.

Solutions Tested

Azure Technologies — LANpharaoh
Protocols Inc. — Foundation Manager
Triticom — LANdecoder/e, LANdecoder/tr, Ethervision, and Tokenvision
Hewlett-Packard Network Test Division — Network Advisor
Network General Corp. — Expert Sniffer
IBM — Dataglance
Siemens Industrial Automation — Protocol Tester K1100
Tekelec — Chameleon 100
Wandel & Goltermann Technologies — DA-30
Alantec — Powerbits 3201
LANquest Labs — Framethrower
Netcom Systems — ET-1000