Network Health

Introduction 3

Interpreting Error Results

propagation time is greater than the minimum legal frame

size of ~57.6 microseconds for 10BASE-T).

 

Collisions

A collision is the result of two or more nodes transmitting at the same time on the segment. Collisions are not necessarily bad. They are a normal part of Ethernet’s operation. In general you need not worry about collisions unless the AVERAGE collision rate is greater than 20%.

Excessive collisions are more often associated with too much network traffic and less often a physical problem with the network. Usually the best way to fix a “collision problem” is to understand why there is excessive traffic.

You may find that the Network Assistant collision count does not agree with that of some protocol analyzers that under report collisions. Just like a Hub, the Network Assistant identifies collisions that occur in the frame’s preamble. These are the most common types of collisions in a 10BASE-T network.

Late Collisions

A late collision is one that occurs after the first 64 bytes in a frame. Consider late collisions a serious network error to be resolved quickly. Late collisions may manifest themselves as frames with a bad Frame Check Sequence (FCS). Late collisions are caused by either a faulty NIC or a network that is too long (i.e., end-to-end signal

Short Frames

A short frame is a frame that is less than the minimum legal size (less than 64 bytes) with a good frame check sequence. In general, you should not see short frames. The most likely cause of a short frame is a faulty card or an improperly configured or corrupt NIC driver file.

Jabbers

A jabber is a frame greater than the maximum legal size (greater than 1518 bytes) with a good or bad frame sequence.

Consider jabbers a serious network error to be resolved quickly. The most likely causes of Jabbers are a faulty NIC or driver or perhaps a cabling problem.

Bad Frame Check Sequence (FCS)

A legal sized frame with a bad frame check sequence (FCS) has been corrupted in some way. Bad FCSs can be caused by late collisions, a faulty NIC/driver, cabling, hub or induced noise.

3-7

Page 46
Image 46
Fluke Series II user manual Interpreting Error Results

Series II specifications

The Fluke Series II is a cutting-edge line of industrial multimeters that incorporates advanced technology and features tailored for professionals working in critical environments. Renowned for their precision and reliability, these multimeters are quintessential tools for technicians and engineers alike, whether in manufacturing, electrical engineering, or maintenance applications.

One of the hallmark characteristics of the Fluke Series II is its robust design. Constructed to endure harsh working conditions, these meters come equipped with a high-impact casing that protects against drops and vibrations. Their IP67 rating ensures they are dust-tight and can withstand temporary immersion in water, making them ideal for fieldwork in tough environments.

The Series II boasts a range of measurement capabilities. With the ability to measure voltage, current, and resistance, as well as additional readings such as frequency, capacitance, and temperature, these multimeters deliver unparalleled versatility. Many models in the Series II also feature True RMS (Root Mean Square) measurement capabilities, enabling accurate readings of non-linear and distorted waveforms, which are increasingly common in modern electronics.

Another significant feature is the advanced display technology. The Series II multimeters often come with large, high-contrast LCDs that facilitate easy reading in various lighting conditions. Some models even offer graphical displays, enabling users to visualize trends in measurement data over time.

User-friendliness is also a hallmark of the Fluke Series II. With intuitive interfaces and simplified navigation, users can access advanced features quickly. Auto-ranging capabilities allow the meter to automatically select the appropriate range for the measurement, minimizing user errors and streamlining the testing process.

Fluke's commitment to safety is underscored by the design of the Series II, which includes features such as safety-rated test leads, protective rubber booting, and a high-voltage warning indicator for added peace of mind.

Moreover, the connectivity options within the Series II enable seamless data transfer to PCs and mobile devices, facilitating easier logging and analysis of measurement data. Many models support Bluetooth or USB connectivity, making it easier than ever to integrate multimeter readings into existing data collection and analysis workflows.

In conclusion, the Fluke Series II multimeters stand out for their durability, versatility, and user-centric features. Their combination of advanced measurement technology, rugged design, and safety functions makes them essential instruments for professionals who demand accuracy and reliability in their work. The commitment to innovation and excellence that Fluke exemplifies ensures that the Series II remains a trusted choice in the field of industrial measurement tools.