Wiring Troubleshooting and Troubleshooting
1. Wiring fault diagnosis technology
1. High-precision time domain reflectometry
2. High-precision time-domain crosstalk analysis technology
3. Compensation technology
4. Optical time domain reflectometry
2. Wiring fault diagnosis
1. Coil fault diagnosis
There are several types of line diagram faults, such as short circuit, reverse connection, wrong pair, and series winding. General test equipment can easily find the first two faults, such as using Fluke's DSP-4300, the test technology is also very simple.
2. Length fault diagnosis
After the cable is too long (exceeds the limit length specified by the link), the link has a large impedance change, which will cause a large signal attenuation. HDTDR technology can be used for positioning.
3. Serial winding fault diagnosis
String faults are hard to spot. The main reason for the string winding error is that the connection module or connector is not made in accordance with ANSI/TIA/EIA 568-B regulations, although the connection of 1-1, 2-2, ..., 8-8 is physically realized, but 1-2, 3-*-5, 7-8 pairs are not guaranteed to be twisted; or the pairs are loosely twisted too long when connecting modules or connectors. Such errors can be detected with the tester's HDTDX technology, which can accurately report the origin and end of a crossover cable, even if the crossover exists in a certain part of the link.
4. Return loss fault diagnosis
Return loss failures are primarily due to link impedance mismatches. Mismatch occurs primarily at the connector, but can also occur in the cable where the characteristic impedance changes. Especially in Gigabit Ethernet, the four pairs of twisted pairs need to transmit in both directions at the same time (full duplex), so the reflected signal will be mistaken for the received signal, resulting in confusion and failure. Return loss faults can be precisely located using HDTDR technology. Such as a link that fails to pass a return loss.
5. Optical cable link fault diagnosis
Factors that affect a fiber optic link include laying the fiber optic cable, the termination of the fiber optic cable double-ended connector, the double-ended patch cord, and the connection of the network equipment. Termination, on the other hand, has the greatest impact on link loss and can cause modal interference to multimode cables.
Effective ways to reduce cable failures in wiring engineering are: ① Remember the strength factor of the optical cable, do not drag the optical cable vigorously, and do not bend the optical cable excessively; ② Clean the connector during installation according to the manufacturer's requirements; ③ Use OLTS according to the standard and OTDR test the installed optical cable; ④ When testing the optical cable link, use a clean jumper and keep it clean at all times; ⑤ All connectors should be equipped with dust cover.
3. Troubleshooting of wiring
1. Troubleshooting of line damage
2. Troubleshooting of open circuit faults in network wiring
3. Troubleshooting of the return loss exceeding the standard
4. Elimination of impedance discontinuity faults
5. Troubleshooting of overlong link faults
6. Troubleshooting the whole network slow down due to optical fiber link
7. Elimination of daisy chain effect
4. Network Health Maintenance Technology
1. What is network health maintenance?
The so-called mission-critical network refers to the applications in which the network owner completely trusts the network. Once the network is out of service and the efficiency is reduced due to network failure or poor performance, the owner company will suffer huge losses. Examples of mission-critical networks are air traffic control networks, financial securities exchange networks, defense and military command networks, and hospital medical networks.
Minimize the frequency and impact of network failures. Specifically, it includes the following measures: 1. The management should participate in the decision-making of the network; 2. Make emergency preparations and plans for failures; 3. Implement preventive measures for possible problems; 4. Comprehensively monitor the network and try to avoid network failures. Early detection; ⑤ Rapid fault isolation and troubleshooting; ⑥ Adopt advanced network monitoring equipment and train management personnel to improve the quality of network management and maintenance. Among them, "comprehensively monitoring the network" and "quick isolation and troubleshooting" are the essence of the "network health maintenance strategy", while "adopting advanced network monitoring equipment and high-quality network management personnel" is the realization of the "network health maintenance strategy" "means and methods. The ultimate goal is to achieve zero-failure network operation.
2. Implementation of network health maintenance
The implementation of network health maintenance is mainly to use advanced network testing equipment, regularly test and monitor the network system, and report the network operation in time, and then quickly eliminate network faults according to the reported results.
The network health maintenance requires that the test instruments used have the ability to identify bad frames without a start of frame identifier (SFD), the ability to monitor "short frames", and the ability to automatically test related network performance.