Network Troubleshooting - Hardware Tools
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Network Troubleshooting - Hardware Tools#
When maintaining and troubleshooting a network, most network engineers prefer to work either up, or down the OSI model – that is to say, they like to check the physical layer and work up, or start with the application layer or work down (If you’ve never heard of the OSI model, you should take a moment to read up on it!). When working with the physical layer, we need hardware tools to check that the actual wires and circuits are functioning as expected. We also need physical tools when installing new network hardware – which is often one of the most fun parts of the job! In this article, we’ll get to know some of the most important ones.
Crimper#
A crimper is a hand tool used for attaching connectors, such as RJ-45 connectors, to the ends of Ethernet cables. It works by compressing the connector onto the cable’s conductors, creating a secure electrical connection. Crimpers are essential for making custom-length cables, which is usually the preferred option when initially wiring in a network.
How it is Used
Crimpers typically have a crimping die that matches the specific connector type (e.g., RJ-45).
After preparing the cable (stripping insulation, arranging wires), the connector is inserted onto the cable.
The crimper is placed over the connector, and pressure is applied to crimp the connector’s contacts onto the cable wires, ensuring a solid connection.
Example When setting up a new network or adding network drops in an office, you would use a crimper to attach RJ-45 connectors to the ends of Ethernet cables. This allows you to connect devices like computers, switches, and access points to the network.
Cable Tester#
A cable tester is a tool used to verify the integrity and connectivity of network cables. It checks for continuity, shorts, opens, and correct wiring in Ethernet cables. If you have an issue at the physical layer, there’s a good chance that a damaged cable is the cause - so this tool is invaluable!
How it is Used
One end of the network cable is connected to the main unit of the cable tester, and the other end is connected to the remote unit.
Activating the cable tester initiates a series of tests, including continuity checks for each wire and detection of faults.
The tester provides clear indications, such as LED lights or a digital display, to show the cable’s condition.
Example In a scenario where network connectivity is unreliable or devices aren’t communicating properly, a cable tester helps identify faulty cables. By connecting the cable tester to both ends of a cable, you can quickly determine if the cable itself is the issue – it’s not unknown for cables to get worn, damaged or even squashed over time, eventually leading to transmission issues.
Punchdown Tool#
A punchdown tool is used for terminating network cables onto keystone jacks, patch panels, or distribution frames. It pushes wire conductors into connectors or slots to establish a secure electrical connection. You’ll use one when installing a new network or replacing faulty cabling (although it’s much less common to have faults with cabling attached to patch panels etc)
How it is Used
The cable is inserted into the appropriate slot on the keystone jack, patch panel, or distribution frame.
The punchdown tool is placed over the wire and connector.
By pressing down on the tool, it pushes the wire conductors into place, creating a reliable connection.
Example When installing structured cabling in a data centre or office building, punchdown tools are used to terminate Ethernet cables onto patch panels. This ensures that the network connections are properly seated, well organized and easily accessible.
OTDR (Optical Time-Domain Reflectometer)#
An Optical Time-Domain Reflectometer (OTDR) is a specialized tool used for testing and troubleshooting optical fiber networks. It sends optical pulses into the fiber and measures the reflected signals to analyze the quality of the fiber link. Although it’s a more complex device, in many ways an OTDR is like a cable tester for fiber.
How it is Used
Connect the OTDR to one end of the optical fiber.
Configure the OTDR settings for the specific fiber type and length.
Activate the OTDR, which sends optical pulses into the fiber.
The OTDR’s output graphically displays the reflected signals, allowing you to analyze the fiber’s quality, detect faults, and measure fiber length.
Example In a data center or telecommunications facility, an OTDR is used to locate and identify issues in optical fiber links. For instance, it can help pinpoint the exact location of a fiber break or measure signal loss along a long-distance fiber optic cable.
Light Meter#
A light meter measures the optical power or intensity of light in fiber optic networks. It helps ensure that optical signals are within the specified power range, which is essential for reliable communication.
How it is Used
The light meter is connected to the optical fiber or connector being tested.
It is set to the appropriate wavelength and power range.
The light meter displays the measured optical power, allowing you to verify that it falls within the acceptable range.
Example In a fiber optic network, it’s crucial to maintain proper signal strength. A light meter is used during installation and maintenance to confirm that optical transceivers are transmitting signals at the correct power levels. If the power is too low or too high, it can affect network performance.
Tone Generator#
A tone generator is used for cable tracing and identifying cables within a bundle. It generates an audible tone along a cable that can be detected using a compatible tone probe – tone generators are very useful for verifying that a cable does indeed go where you think it goes (over time, this tends not to always be the case!)
How it is Used
The tone generator is connected to one end of the cable.
It emits an audible tone signal that travels through the cable.
A compatible tone probe is used to trace and locate the cable within a bundle by following the audible tone.
Example Imagine you have a large bundle of Ethernet cables in a server room, and you need to identify a specific cable that runs to a particular workstation. You can use a tone generator to send a signal through the cable and then use a tone probe to follow the audible tone to locate the correct cable. When you touch the probe to the end of the table to which the tone generator is attached, you hear the tone – simple, but hugely effective!
Loopback Adapter#
A loopback adapter, often used with Ethernet connections, allows for self-testing by physically looping transmitted signals back to the sender. It is used to verify network interface card (NIC) functionality and test network ports.
How it is Used
The loopback adapter is inserted into the network port (e.g., Ethernet port) you want to test.
The adapter loops the transmitted signals back to the NIC.
You can then test the NIC’s ability to transmit and receive data by sending and receiving data packets.
Example If you suspect that a network port on a switch or router is not functioning correctly, you can use a loopback adapter to verify if the port itself is operational. By connecting the adapter to the port, you can send data and check if it’s successfully looped back, indicating that the port is functional.
Multimeter#
A multimeter is a versatile electrical measurement tool used to measure various parameters such as voltage, current, resistance, and continuity. It is invaluable for diagnosing electrical issues in network equipment and connections, and in many other electrical scenarios.
How it is Used
Select the appropriate measurement mode (e.g., voltage, current, resistance) on the multimeter.
Connect the multimeter probes to the circuit or component being tested.
The multimeter provides readings on its display, allowing you to determine the measured value.
Example Suppose you are troubleshooting a network device that is not receiving power or experiencing electrical issues. You can use a multimeter to measure the voltage at the power source or check the continuity of cables and connectors to identify any electrical faults.
Spectrum Analyzer#
A spectrum analyzer is an advanced tool used for analyzing the frequency spectrum of signals. It is commonly used in radio frequency (RF) and wireless network troubleshooting to visualize and analyze signal characteristics.
How it is Used
Connect the spectrum analyzer to the RF or wireless device, antenna, or signal source.
Configure the spectrum analyzer settings, including frequency range and bandwidth.
The spectrum analyzer displays a graphical representation of signal strength and frequency distribution in real-time.
Example In wireless networking, a spectrum analyzer can help identify sources of interference in the RF spectrum. For instance, if a Wi-Fi network is experiencing poor performance, the spectrum analyzer can reveal if neighbouring devices or non-Wi-Fi interference (e.g., microwaves) are causing signal degradation.
Final words#
When working with physical equipment, Hardware tools are essential for maintaining, troubleshooting, and optimizing network infrastructure, both in wired and wireless environments. When used correctly, they enable network professionals to ensure network reliability, performance, and functionality, as well as troubleshoot and resolve various network issues. Keep in mind that while some of these tasks (like identifying a cable) seem simple enough in a small environment, network engineers will often need to perform these tasks in networks with thousands of connections – in this context, you can see how much time the right tool can save!