System information

Third-Party Troubleshooting Tools
Book Title
2-14
Monitors collect information such as packet sizes, the number of packets, error packets, overall
usage of a connection, the number of hosts and their MAC addresses, and details about
communications between hosts and other devices. This data can be used to create profiles of LAN
traffic as well as to assist in locating traffic overloads, planning for network expansion, detecting
intruders, establishing baseline performance, and distributing traffic more efficiently.
Network Analyzers
A network analyzer (also called a protocol analyzer) decodes the various protocol layers in a
recorded frame and presents them as readable abbreviations or summaries, detailing which layer is
involved (physical, data link, and so forth) and what function each byte or byte content serves.
Most network analyzers can perform many of the following functions:
• Filter traffic that meets certain criteria so that, for example, all traffic to and from a particular
device can be captured
• Time stamp captured data
• Present protocol layers in an easily readable form
• Generate frames and transmit them onto the network
• Incorporate an “expert” system in which the analyzer uses a set of rules, combined with
information about the network configuration and operation, to diagnose and solve, or offer
potential solutions to, network problems