6.08 Use networking tools
Introduction
Think of a network like the foundation of a building—if the right materials aren't used, the structure won’t be strong or reliable. In networking, using the correct cables and connectors is just as important to ensure data flows efficiently without interruptions.
Whether you're setting up a home network or managing a larger system, knowing which cables to choose and how to properly install them with the right tools is essential. With this knowledge, you’ll be able to optimize network performance and prevent future issues, ensuring everything runs smoothly and supporting others in maintaining reliable connections.
Unshielded Twisted Pair (UTP)
Unshielded Twisted Pair (UTP) is the most common type of network cable made of copper wires. It’s popular for connecting computers and devices in a network.
Key Features of UTP Cable:
Structure: UTP consists of four pairs of copper wires.
Twisted Pairs: Each pair of wires is twisted together at a different rate to reduce interference from outside signals.
Electrical Signaling:
Balanced Signals: Electrical signals sent through UTP are balanced. This means each wire in a pair carries an equal but opposite signal. This helps the network detect signals better and reduces interference.
Limitations of UTP:
Attenuation: Over long distances, the signal gets weaker, a process known as attenuation.
Range: UTP cables are typically reliable for distances up to 100 meters (328 feet). Beyond this, the signal may degrade too much to be useful.
Shielded Twisted Pair (STP)
Shielded Twisted Pair (STP) is a type of network cable designed to provide extra protection against interference. It's commonly used in 10G Ethernet and higher within datacenter networks because it's more reliable than Unshielded Twisted Pair (UTP).
When to Use STP:
In environments with high levels of interference such as:
Fluorescent lighting
Power lines
Motors
Generators
Types of Shielded Twisted Pair:
There are different types of shielding used in STP cables:
Screened Cable:
Has a thin outer foil shield around all the wire pairs.
Often labeled as:
Screened Twisted Pair (ScTP)
Foiled/Unshielded Twisted Pair (F/UTP)
Sometimes called Foiled Twisted Pair (FTP).
Fully Shielded Cable:
Contains both a braided outer screen and foil-shielded pairs.
Labeled as Shielded/Foiled Twisted Pair (S/FTP).
Some versions have just a foil outer shield, called F/FTP.
Example:
F/UTP cable: Has a foil screen around the unshielded wire pairs.
Shielding and Interference Prevention:
The shielding elements in STP cables must be bonded to the connectors. This prevents the metal shielding from acting like an antenna, which could cause interference.
Modern Solutions:
Newer F/UTP and S/FTP designs use special connectors and patch panels that include bonding to manage shielding and prevent interference.
Understanding Cat Standards for Network Cables
A Cat (Category) specification refers to the construction method of twisted pair cables and determines its capability to support different Ethernet standards. Higher Cat specifications allow for faster data transfer rates.
Key Cat Specifications
Below are the most common Cat standards and their specifications:
Cable Identification and Usage
The Cat specification is printed on the cable jacket along with the cable type, such as UTP or F/UTP.
Cat 5: Supports 100 Mbps Fast Ethernet but is no longer commercially available. Networks using Cat 5 likely need to upgrade to support Gigabit Ethernet.
Cat 5e: Can still be used for Gigabit Ethernet (1 Gbps), especially for client computers. Most sites prefer Cat 6 for improved reliability.
Advantages of Cat 6 and Cat 6A
Cat 6:
More reliable than Cat 5e for Gigabit Ethernet.
Supports 10 Gbps but only up to 55 meters (180 ft).
Cat 6A:
Can handle 10 Gbps over 100 meters (328 ft).
Bulkier and heavier than Cat 5e and Cat 6.
Installation is more complex, making it harder to fit into pathways designed for older cables.
Recommended Use Cases
Cat 6A is recommended for:
Healthcare facilities.
Power over Ethernet (PoE) installations (802.3bt).
Connecting wireless access points in distribution systems.
Copper Cabling Connectors Explained
Copper cabling connectors are essential for setting up Ethernet networks. They allow twisted pair cables to connect devices like computers, switches, and routers.
Types of Connectors
RJ45 Connectors (8P8C):
RJ45 stands for Registered Jack 45 and is also known as 8P8C, meaning eight-position/eight-contact.
Used for Ethernet connections with twisted pair cables.
RJ11 Connectors:
Typically used for telephone systems and DSL modems.
Designed for two-pair cables instead of the four-pair cables used in Ethernet.
Color-Coding of Wires
Ethernet cables have four pairs of wires, each with specific colors to help with proper connections:
Orange Pair:
White with orange stripes
Solid orange
Green Pair:
White with green stripes
Solid green
Blue Pair:
White with blue stripes
Solid blue
Brown Pair:
White with brown stripes
Solid brown
Each wire in a pair has a predominantly white insulator with a colored stripe or a solid color insulator.
Termination Standards: T568A and T568B
The TIA/EIA-568 standard defines how to terminate Ethernet cables using two methods:
T568A Standard
Pin 1: Green/White
Pin 2: Green
Pin 3: Orange/White
Pin 6: Orange
T568B Standard
Pin 1: Orange/White
Pin 2: Orange
Pin 3: Green/White
Pin 6: Green
Choosing the Right Termination Method
Consistency is Key: Always use the same termination standard (either T568A or T568B) on both ends of the cable.
Straight Through Cables:
Have the same termination method at both ends.
Used to connect different devices, like a computer to a switch.
Crossover Cables:
Use T568A on one end and T568B on the other.
Originally used to connect similar devices directly, such as two computers.
Modern Gigabit Ethernet can automatically adjust for crossover, making them less necessary.
Using RJ11 Connectors
RJ11 is used with twisted-pair cables for:
Telephone systems
Broadband DSL modems
Unlike RJ45, which uses four pairs of wires, RJ11 typically uses two pairs.
Key Takeaways
RJ45 (8P8C) connectors are standard for Ethernet networking.
Color-coded wires ensure proper connections and reduce errors.
T568A and T568B are the two termination standards; choose one and stick with it for consistency.
Straight through cables connect different types of devices, while crossover cables connect similar devices, though they are less needed with modern technology.
RJ11 connectors are used for telephone and DSL connections, not for Ethernet.
Copper Cabling Installation Tools
Installing copper cabling for an office network follows a structured process, requiring specific tools. Each computer’s network adapter is connected to a wall port using a patch cord, while the permanent cabling runs behind walls to a patch panel connected to an Ethernet switch.
Types of Cable Termination
A structured cabling system uses two main types of terminations:
Patch Cords: Terminated using RJ45 plugs crimped to the end of the cable.
Permanent Cables: Terminated at wall ports and patch panels using insulation displacement connectors (IDCs), also called punchdown blocks.
IDC’s (punchdown blocks)
The total distance for this cabling, called the channel link, should not exceed 100 meters (328 feet). Patch cords can only be 5 meters (16 feet) long, while permanent cables use solid cables with thicker wires. Patch cords use stranded cable with thinner wires, which are more flexible but can lose signal strength faster (attenuation).
Essential Installation Tools
To install and terminate cables, several specialized tools are required:
Cable Stripper and Snips
Cable Stripper:
Removes the outer jacket of the cable to expose the wire pairs without damaging their insulation.
The tool must be set to the correct diameter and rotated to create a cut in the jacket, allowing the jacket to be removed easily.
Snips (Electrician's Scissors):
Cat 6 and Cat 6A cables often have a plastic star filler to keep the wire pairs separated.
Use snips to cut off the star filler.
There may also be a nylon thread (ripcord), which can be pulled to open the jacket further if needed. Trim any excess ripcord before terminating the cable.
Punchdown Tool
Punchdown Tool: Used to secure each conductor into the IDC (Insulation Displacement Connector).
Steps:
Untwist the wire pairs and lay them in the color-coded terminals of the IDC.
Follow the proper wiring order (either T568A or T568B).
Only untwist up to ½ inch (13 mm) to minimize interference.
Use the punchdown tool to press each wire into the terminal, allowing the blades to cut through the insulation and make electrical contact.
Crimper
Crimper: Used to attach an RJ45 plug to a patch cord.
Steps:
Align the RJ45 plug so the tab latch is facing down.
Arrange the wires according to the wiring order (T568A or T568B).
Push the wires into the plug and use the crimper to press them into place.
The crimper will pierce the insulation and secure the plug to the outer jacket.
Copper Cabling Test Tools
After terminating cables, it’s essential to test them to ensure proper electrical contact and correct pin positions. Testing right after installation is crucial, as it’s easier to fix errors while you still have access to the cables. There are several tools available to assist in testing and troubleshooting the cabling.
Cable Tester
A cable tester is a tool used to check if each wire in a cable is properly connected. It consists of two devices attached to each end of the cable. You can use it to test:
Patch cords by connecting the tester to both ends of the cord.
Permanent links by connecting the tester to a wall port and a patch panel port.
How It Works:
The tester sends a signal through each wire, one by one.
If a wire is correctly connected, the LED on the tester will light up.
If the LED does not light up, there may be an issue with the wire (such as a break or improper connection).
If the LEDs light up in a different order at each end, it means the wires are not terminated in the same sequence, and both ends need to use the same wiring standard (T568A or T568B).
Toner Probe
A toner probe is a tool that helps identify cables when they are not labeled properly or when multiple cables are bundled together.
How It Works:
A tone generator sends an audio signal through the cable.
The probe detects the tone, allowing you to trace the cable through ceilings, ducts, or a bundle of cables.
Loopback Plug
A loopback plug is used to test the functionality of a network interface card (NIC) or switch port.
How It Works:
A basic loopback plug connects pin 1 to pin 3 and pin 2 to pin 6 of an RJ45 connector.
When plugged into a port, a solid link LED indicates that the port can both send and receive signals.
Important: Make sure the other end of the cable is disconnected from network equipment before using the toner probe to avoid damage.
Network Taps
A network tap is a device used to capture data traveling over a network cable. The data is then sent to a packet or protocol analyzer for monitoring and analysis. There are two types of network taps: passive and active.
Passive TAP
A passive test access point (TAP) is an unpowered device that intercepts and copies network signals without altering them. It includes:
Ports: One for incoming network cabling and one for outgoing.
Signal Copying: Uses an inductor or optical splitter to physically duplicate the signal and send it to a monitor port.
Key Features of Passive TAPs:
The monitor port receives every frame, including corrupted or malformed ones.
Signal copying is not affected by network load.
No power is required, making it a reliable option for monitoring without becoming a point of failure.
Active TAP
An active TAP is a powered device that performs signal regeneration. This may be needed when the signal is too complex for a passive TAP to handle, such as with Gigabit Ethernet or certain types of fiber optic links.
Key Features of Active TAPs:
It regenerates signals, ensuring data is accurately captured.
It is necessary for Gigabit Ethernet over copper, as passive TAPs cannot handle the complexity of this signal.
It can also be used with fiber optic links where passive splitting could weaken the signal.
Note: Since an active TAP requires power, it can become a point of failure if there is a power outage, disrupting the network link.
Using SPAN/Mirror Ports
Network sniffing can also be performed using a switched port analyzer (SPAN) or mirror port. Instead of using a physical tap, a switch is configured to send copies of network frames to a specific port, known as the mirror port.
Key Features of SPAN/Mirror Ports:
The mirror port receives copies of the frames addressed to specific access ports or all ports on the switch.
This method allows for network monitoring without the need for a separate physical tap.
Copper Cabling Installation Considerations
When installing copper cabling, it’s important to follow local building regulations and fire codes. This means certain types of cables must be used in specific situations to ensure safety and compliance.
Plenum Cable
A plenum space is a hidden area in a building, often used for heating, ventilation, and air conditioning (HVAC) systems. It is typically located in false ceilings or raised floors. Since plenum spaces allow for easy airflow, they can also spread fire quickly.
Requirements for Plenum Cable:
Fire-Retardant: Plenum cables must be fire-resistant, self-extinguishing, and emit minimal smoke when burned.
Materials: Plenum-rated cables are made of treated PVC or fluorinated ethylene polymer (FEP), which makes them less flexible but does not impact data transfer speed.
Cable Markings:
Plenum-Rated Cable: Marked as CMP/MMP under the US National Electrical Code (NEC).
General Purpose Cable: Uses standard PVC jackets and is marked CMG/MMG or CM/MP.
Direct Burial Cable
Outside plant (OSP) cable is used for installations outside buildings or between buildings. This type of cable must withstand weathering and other environmental factors.
Types of OSP Installations:
Aerial Cable: Strung between poles or anchors and exposed to UV rays, temperature changes, and moisture, which degrade regular PVC cables.
Conduit Cable: Buried underground in protective conduits but still exposed to temperature extremes and dampness.
Direct Burial Cable: Laid directly in the ground or covered with cement/concrete. This type of cable requires extra protection, such as:
Special coatings to protect against UV rays and abrasion.
Gel filling to protect against moisture and temperature extremes.
Armored cables to guard against rodents.
Optical Cabling Overview
Unlike copper cables that carry electrical signals and are prone to interference and attenuation, optical cabling uses light pulses, making it more resistant to interference and able to transmit data over much longer distances. Optical cables can handle extremely high bandwidth, measured in gigabits or even terabits per second, with cable runs spanning miles rather than feet.
Structure of Fiber Optic Cables
A fiber optic cable consists of several layers:
Core: The ultra-thin glass core where light pulses travel.
Cladding: Surrounds the core and helps guide the light along the fiber.
Buffer: Provides protection to the cladding.
Protective Jacket: The outer layer that shields the fiber optic strands from damage.
Single-Mode Fiber (SMF)
Core Size: 8–10 microns (extremely small).
Signal Type: Carries a long-wavelength infrared signal (1,310 or 1,550 nm) generated by a high-powered, coherent laser diode.
Data Rates: Supports data rates up to 10 Gbps or more.
Distance: Can handle long distances (many kilometers) depending on the quality of the cable and optics.
Use Case: Ideal for long-distance communication, such as WANs (Wide Area Networks).
Types of Fiber Optic Cables
There are two main categories of fiber optic cables:
Multi-Mode Fiber (MMF)
Core Size: 50 or 62.5 microns (larger than SMF).
Signal Type: Carries shorter-wavelength infrared light (850 nm or 1,300 nm) generated by less expensive LEDs or VCSELs (Vertical Cavity Surface Emitting Lasers).
Data Rates: Supports lower data rates compared to SMF.
Distance: More suitable for shorter distances (typically used in LANs).
Use Case: More affordable and easier to deploy than SMF, commonly used in local area networks (LANs).
Fiber Optic Connectors
Fiber optic connectors ensure a continuous reception of light signals. The core of the connector is typically a ceramic or plastic ferrule that aligns the fibers. There are various connector types based on different locking mechanisms and use cases:
Common Connector Types:
Straight Tip (ST):
Uses a bayonet-style push-and-twist lock.
Commonly found in older multi-mode networks.
Subscriber Connector (SC):
Features a push/pull design for easy insertion and removal.
Available in simplex (single connector) and duplex (two connectors clipped together) versions.
Suitable for both single-mode and multi-mode networks.
Lucent Connector (LC):
A small form factor connector with a tabbed push/pull design.
Similar to SC but with a smaller size, allowing for higher port density.
Patch Cords and Connectors
Patch cords for fiber optics can have the same type of connector on both ends (e.g., ST-ST) or mixed connectors (e.g., ST-SC). Since fiber optic connectors are delicate, they should not be plugged and unplugged frequently. Unused ports and connectors must be covered with dust caps to prevent contamination.
Coaxial Cabling Overview
Coaxial (coax) cable is another type of copper cable that carries electrical signals. Unlike twisted pair cables, coax uses two conductors that share the same axis to minimize interference.
Structure of Coaxial Cable
Coaxial cables consist of several layers:
Core Conductor: The central wire that carries the signal.
Plastic Insulation (Dielectric): Surrounds the core conductor to provide insulation.
Wire Mesh Conductor: Acts as a shield against electromagnetic interference (EMI) and serves as a grounding layer.
Protective Jacket: Covers the outer layer of the cable for additional protection.
F-Type Connector
Coaxial cables used in CATV installations are usually terminated with an F-type connector.
F-Connector: Features a pin that screws into the device, securing the connection.
Common Uses of Coaxial Cable
Coaxial cables are now primarily used in:
CCTV installations (closed-circuit television).
Cable Access TV (CATV) systems.
Broadband cable modems as patch cables.
Summary
Great job on learning about the essential tools and components used in networking! You've explored everything from the differences between UTP and STP cables, to the various Cat standards that determine data transfer speeds, and the specialized tools required for proper cable installation and testing. You've also delved into fiber optics, a powerful medium for high-speed data transmission over long distances, and learned about coaxial cables, still widely used for CCTV and cable modems. Your growing knowledge of these technical areas is impressive and will empower you to set up and troubleshoot networks confidently. Keep up the great work!