Ethernet Test Tools

Hardware

TDR (Time-Domain Reflectometer) - a tool used to detect cable faults. This device operates by sending a brief signal pulse down the cable and looking for its reflection to bounce back. By analyzing the reflected pulse, it is possible to make judgments about the quality of the cable segment. More advanced units can not only detect and identify the nature of the problem, but give a reasonably accurate indication of the problem's location (distance from the point of the test). There is also a device known as an OTDR, which is an Optical Time-Domain Reflectometer for fiber-optic cables.

BERT (Bit Error Rate Tester) - this equipment is used to analyze the amount and types of errors that occur on a cable segment.  All telco techs carry a BERT in their truck.

Software

There are many free utilities built into most systems. For example, the ping command can be used to determine if a given host is alive, and will also tell you the round trip transmission time.  TraceRoute will ping each successive device along the path and built a list for you.

With Windows systems, winipcfg (Win98) and ipconfig (Win2000-XP) will list the MAC and IP addresses of your interfaces, release and renew IP addresses, etc.

With UNIX systems, ifconfig will tell you the status of the network interfaces. netstat will summarize statistics for network usage. spray will allow you to generate network traffic directed at a particular host. Use "man
command-name" to learn more about a unix command. Using "man -k network" may also provide leads to the tools provided by your unix vendor.

Many more public domain tools are available for unix systems.  These include:

• traffic: allows systems to graphically display network load
• tcpdump: collect statistics and display individual packets
• etherfind: ????
• nfswatch: summarize/display traffic, particularly nfs packets
• traceroute: determine the route between two hosts

Some cards for the PC come with utilities. There are several free ones available, including ping (Clarkson University and others),
The Beholder (packet capture and display) and others.