This is because WANs often have many different physical interfaces, link parameters, and protocols. To meet that challenge, WAN testers come with a large and often confusing array of software and controls, and they usually must be configured manually before data can be captured. While the more powerful network analyzers have some features formerly confined to dedicated protocol analyzers, the latter remains the most functional network-diagnostic tool. By decoding packets as they travel through the network, these devices can analyze all network activity. They are used to locate problems from Layers 2 to 6.
Protocol analyzers can be either hardware or software.
In general, the more functionality the tester provides, the more expertise is needed to interpret its findings. A technician can learn to use a cable tester in half an hour or a low-end LAN analyzer in half a day. But to use all the functions of a WAN tester or protocol analyzer, you need to be network-savvy. To reduce the required experience level of the operator, some devices now come with expert systems. Without an expert system, the devices merely display numbers, leaving the operator to make the diagnosis.