Network Tools - CompTIA A+ 220-1101 - 2.8

Summary

This script offers an in-depth guide to cable management and network troubleshooting. It covers the use of cable crimpers for attaching connectors to various cable types, the importance of using the right tools for wire stripping and cutting, and the process of crimping RJ45 connectors. It also discusses wireless network analysis with Wi-Fi analyzers, identifying cables with tone generators, and the meticulous work of punch down blocks. The script concludes with the utility of cable testers, advanced TDR tools, loopback plugs for interface testing, and the application of physical network taps for traffic monitoring.

Takeaways

• 🔌 Crimping is a crucial step in cable installation, requiring a specialized tool known as cable crimpers to attach connectors to the cable ends.
• 🛠️ There are various types of crimpers for different cable types, such as coaxial, twisted pair, and fiber, each designed for specific connector attachment.
• 🔄 RJ45 connectors are used for twisted pair cables and involve prongs that pierce the insulation to establish a connection with the copper wire inside.
• ✂️ Essential tools for cable installation include cable crimpers, electrician scissors or cable snips, and a wire stripper for efficient cable preparation.
• 📡 Understanding cable types is important; for instance, category 5, 6, or 7 cables require the appropriate connectors for proper installation.
• 📊 A Wi-Fi analyzer is a valuable tool for monitoring wireless networks, providing insights into frequency usage and potential interference.
• 🔍 A tone generator and inductive probe are used to identify specific cables in a complex network by emitting a signal that can be traced.
• 📌 Punch down blocks require a specialized tool for making permanent cable connections, and maintaining cable organization is vital for efficient management.
• 🔄 Ethernet cables should maintain their twist as much as possible, which is important for signal integrity and is preserved even in punch down blocks.
• 🔍 Cable testers are essential for verifying the continuity and correct connection of cables, while advanced tools like TDR can measure signal loss and crosstalk.
• 🔄 Loopback plugs and cables are used for testing interfaces by sending data out of an interface and back into the same device, useful for troubleshooting mismatches.
• 🌐 Physical network taps or switch port analyzers allow for monitoring the data traversing between devices, useful for troubleshooting and traffic analysis.

Q & A

What is the purpose of cable crimpers in cable installation?

Cable crimpers are tools designed to add connectors onto the end of a cable, which is a common practice when running new cables without connectors already attached.

What types of cables can crimpers be used for?

Crimpers can be used for various cable types including coaxial cables, twisted pair cables, and fiber cables, with different crimpers designed for each type.

What is the final step in the cable installation process after running the cable through the floor or ceiling?

The final step is adding a connector to the end of the cable on both sides using a crimper, ensuring a secure connection for the device being plugged in.

How do crimpers work with twisted pair cables?

Crimpers for twisted pair cables push prongs through the insulation and into the copper wire, creating a connection that extends the copper inside the wire to the copper connections on the RJ45 connector.

What is the importance of a good crimp on an RJ45 connector?

A good crimp ensures that the cable wires make a secure connection with the RJ45 connector, with all wires running to the top of the connector and the cable stay at the bottom holding the entire cable in place.

What tools are recommended for running your own cable besides a crimper?

Besides a crimper, a good pair of electrician scissors, also known as cable snips, and a wire stripper are recommended for efficiently running your own cable.

Why is it important to use the right connector for the type of cable being used?

Using the correct connector for the cable type, such as category 5, 6, or 7, ensures compatibility and optimal performance of the cable in the network.

What is a Wi-Fi analyzer and how does it help in understanding a wireless network?

A Wi-Fi analyzer is a tool, either software or hardware, that listens to signals on a wireless network, providing information about used frequencies and potential open ones, which helps in understanding and managing network interference.

What is a tone generator and how does it assist in identifying cables in a large network?

A tone generator adds a signal to a copper wire, used in conjunction with an inductive probe to identify specific cables in a complex network by emitting a tone that can be detected without physical contact.

What is the purpose of a punch down block and how is it used?

A punch down block is used to permanently connect individual wires from a cable into specific slots, using a punch down tool that fastens the wires and trims excess, ensuring a neat and organized connection.

Why is maintaining the twist in an Ethernet cable important and how is it achieved?

Maintaining the twist in an Ethernet cable reduces crosstalk and signal interference, which is achieved by keeping the twist intact all the way to the punch down block or connector.

What is the role of a cable tester and how does it help in cable installation?

A cable tester checks for continuity and correct pin-to-pin connections in a cable, identifying any missed or crossed wires, ensuring a properly functioning cable installation.

What is a loopback plug and how is it used for troubleshooting network interfaces?

A loopback plug is used to send data out of an interface and immediately back into the same device, allowing for comparison of sent and received data to identify problems with the physical interface.

What is a physical network tap and how does it facilitate network troubleshooting?

A physical network tap disconnects a link and places itself in the middle, copying all data passing through and sending it to an analyzer, providing visibility into the traffic for troubleshooting purposes.

What is the difference between a crossover cable and a loopback cable?

A crossover cable connects two devices directly to each other, while a loopback cable connects a device to itself, allowing for testing of the interface without involving another device.

Outlines

00:00

🔌 Crimping Connectors for Cable Installations

This paragraph discusses the process of attaching connectors to the ends of cables without connectors, using a specialized tool known as cable crimpers. These tools, similar to pliers, are designed to add connectors to various types of cables such as coaxial, twisted pair, or fiber. The paragraph explains the final step of cable installation, which involves running the cable through floors or ceilings and then crimping the connectors onto the cable ends. It details the use of RJ45 connectors for twisted pair cables, demonstrating how the crimper pushes prongs through the insulation to establish a connection with the copper wire. The importance of using the correct type of connector for different cable categories is also highlighted, along with the suggestion to practice the process of cutting the cable sheath, inserting wires into the connector, and crimping. The paragraph concludes with a mention of tools like electrician scissors and wire strippers, and the use of Wi-Fi analyzers for understanding wireless network frequencies and potential interference.

05:02

🔍 Identifying and Testing Network Cables

The second paragraph delves into the tools and techniques used for identifying and testing network cables. It begins with the use of a tone generator and inductive probe to locate specific cables within a bundle, demonstrating how the probe detects a signal from the tone generator attached to one of several Ethernet cables. The paragraph then describes the process of connecting wires to a punch down block using a specialized tool, emphasizing the importance of organization and documentation in managing multiple cables. The maintenance of cable twists in Ethernet cables is also discussed, along with the use of cable testers for continuity checks and the identification of cable issues such as missed or crossed wires. Advanced tools like Time Domain Reflectometers (TDR) for more detailed cable analysis are mentioned, as well as loopback plugs and physical network taps for troubleshooting network interfaces and capturing data traffic. The paragraph concludes with a brief mention of port mirroring or SPAN on switches as a simple method for capturing data traffic for analysis.

10:02

🛠️ Advanced Network Troubleshooting Tools

The final paragraph focuses on advanced tools for network troubleshooting. It describes the use of a physical tap to break the connection between two devices and insert itself to create a copy of the data traffic, which can then be monitored using a protocol analyzer. The paragraph explains the physical tap's operation, including how it captures and duplicates data flowing between devices, allowing for traffic analysis. It also touches upon the design of the tap and how it fits into the network infrastructure, providing a clear and comprehensive understanding of how to use such a device for network monitoring and troubleshooting.

Keywords

💡Cable Crimper

A cable crimper is a specialized tool used to attach connectors to the ends of cables. It is crucial in the process of cable installation, as it ensures a secure and reliable connection. In the video, crimpers are described as resembling pliers but are specifically designed for this purpose. The script mentions different types of crimpers for various cable types, such as coaxial, twisted pair, or fiber, and demonstrates how an RJ45 connector is crimped onto an Ethernet cable.

💡RJ45 Connector

An RJ45 connector is a type of electrical connector commonly used for Ethernet networking. It has eight pins and is designed to transmit data signals. The video script describes the process of inserting a cable into the back of an RJ45 connector and crimping it to establish a connection with the copper wires inside. The script also illustrates the importance of a good crimp, showing how the copper connections should extend into the connector to ensure a secure link.

💡Wire Stripper

A wire stripper is a tool used to remove the outer insulation from a wire in preparation for connecting or splicing. In the context of the video, a wire stripper is recommended for quickly removing the sheath from Ethernet cables, which is a necessary step before the cable can be inserted into a connector and crimped.

💡Ethernet Cable

Ethernet cables are a type of networking cable used to connect devices within a local area network (LAN). The video script discusses running Ethernet cables through floors or ceilings and the process of adding connectors to both ends. It also touches on different categories of Ethernet cables, such as Category 5, 6, or 7, and the importance of using the correct connector for each type.

💡Wi-Fi Analyzer

A Wi-Fi analyzer is a device or software application that listens to signals on a wireless network and provides information about the frequencies in use. The video mentions using a Wi-Fi analyzer to understand what's happening over the air, including identifying open frequencies and potential interference points. This tool is particularly useful in areas with many Wi-Fi access points.

💡Tone Generator

A tone generator is a device used to identify specific cables in a complex network by sending a signal onto the copper wire. The video script describes how a tone generator, in conjunction with an inductive probe, can help locate a specific cable among many in a data center. This tool is essential for troubleshooting and managing large networks.

💡Punch Down Block

A punch down block is a type of electrical connector used in telecommunication systems, allowing individual wires to be connected to it. The video script explains the process of using a punch down tool to fasten wires into the block, which involves both inserting the wire into the block and cutting off excess wire to create a neat connection.

💡Cable Tester

A cable tester is a device used to check the continuity and integrity of a cable by performing tests to ensure that each pin is connected correctly. The video script mentions that cable testers can indicate if wires are missed or not punched down properly, but they may lack advanced functionality like measuring crosstalk or signal loss.

💡Loopback Plug

A loopback plug is a device used in networking to test the interface of a device by sending data out of an interface and back into the same device. The video script describes how a loopback plug can help identify problems with a physical interface by comparing the sent and received data.

💡Physical Network Tap

A physical network tap is a device that allows a copy of all data transmitted between two devices to be sent to an analyzer. The video script explains that a network tap can be used to see the data on a connection, which is helpful for troubleshooting. It can be a passive or active tap, depending on whether it requires power or not.

💡Port Mirror (SPAN)

Port mirroring or SPAN (Switched Port Analyzer) is a function built into network switches that duplicates data from one or more ports to a monitoring port. The video script mentions port mirroring as a simple and temporary solution for capturing network traffic for analysis, which is useful when a physical tap is not available.

Highlights

Cable crimpers are essential tools designed to add connectors onto the end of various types of cables, such as coaxial, twisted pair, or fiber cables.

For twisted pair cables, crimpers push prongs through the insulation into the copper wires, ensuring a secure connection inside the RJ45 connector.

When using a crimper, the copper connections are pushed down into the wires, creating a secure link between the cable and the device.

It's crucial to use the correct connector type for the specific category of cable being used, such as Cat5, Cat6, or Cat7.

Electrician scissors, cable snips, and wire strippers are recommended tools to complement crimping for effective cable management.

Wi-Fi analyzers are valuable tools for monitoring wireless network frequencies, identifying interference, and optimizing network performance.

Tone generators and inductive probes are useful for locating specific cables in environments with numerous wires, like data centers.

Punch down blocks require precise organization, as each wire must be individually secured into the block, with good documentation for easy management.

Maintaining the twist in twisted pair cables as close to the punch down block as possible is critical for minimizing signal loss and crosstalk.

Cable testers can verify the continuity of connections, ensuring that each pin in the cable is correctly wired and functioning.

Loopback plugs and cables are used to test the interface of a device by sending data out and immediately back into the same device.

Physical network taps allow for direct monitoring of network traffic by inserting the tap between two devices, providing a copy of the data for analysis.

Port mirroring or SPAN (Switched Port Analyzer) is a switch feature that duplicates traffic from one or more ports and sends it to another port for monitoring.

Active and passive taps can be used depending on the connection type; active taps require power and are typically used for copper connections.

Proper documentation and labeling of punch down blocks and cables are essential for maintaining organization and troubleshooting in complex network setups.

Transcripts

When are you running new cables, it's

very common to run the cable itself

without any connectors on the end.

So you need a tool that's specially designed

to add those connectors onto the end of the cable.

We call these cable crimpers And they

look very similar to a pair of pliers,

but they're actually very specially

designed to add that connector onto the end of the cable.

There are different types of shrimpers that you can use.

And they're designed to add a connector

onto the end of coaxial cables, twisted pair cables, or fiber.

This is usually the final step in the process.

You've already run the cable through the floor

or the ceiling, and you have the cable

on both sides that need to have a connector added

to the end of those cables.

For twisted pair cables, these crimpers

are pushing prongs through the installation

and into the copper in the wire itself.

Here's an RJ45 connector before it's used inside of a crimper.

The cable would obviously be put into the back of this RJ45

connector.

And you can see the copper connections

at the end of the RJ45 connection.

You can see the copper connection sitting just

above the RJ45 connector here.

And when you use the crimper, it pushes down all

of those connectors into the wire.

Where the wires are connecting, you can see these sharp prongs

at the bottom that are pushed through the insulation

to make a connection with the copper inside

of each individual strand.

This extends that copper inside of the wire

into these copper connections which

then connect to the device that you're plugging into.

After making the crimp, you can see

that those connectors have been pushed down

into the RJ45 connector.

And you can see where those spiky ends of that copper

connector have now made a connection

into the wires that are inside of that RJ45 connector.

If we look at the bottom of this RJ45 connector,

you can see the copper that is on the outside

of this connection, and that's the copper

that will be used by the device we're connecting to.

This particular image is a very good crimp.

You can see that the cables run all the way to the top

of the RJ45 connector.

It looks like they all have made very good connection

into the wires themselves.

And there is a cable stay at the bottom of that connector that

pushes into the sheath to help hold the entire cable in place.

If you're running your own cable,

then you'll need a crimper to be able to add

that RJ45 connector onto the end of the ethernet cable.

You might also want to get a good pair of electrician

scissors.

These are sometimes referred to as cable snips.

And a nice wire stripper can be used

to quickly remove the wiring sheath from the outside

of the ethernet wires.

There are differences in wire types.

So if you're using category 5 versus category 6 or category 7

cable, then there will be different connectors

for each of those cable types.

You want to make sure you're using

exactly the right connector for the type of cable

that you're using.

This takes a little bit of practice,

but once you become accustomed to cutting the cable sheath,

putting the wires into the RJ45 connector in the right order,

and crimping them down, you'll find

that you're able to make your own custom cables.

If you're working with a wireless network,

then you don't have to spend a lot of time crimping cables.

But you do have to spend time understanding

all of the different frequencies that are in use

on that wireless network.

To be able to understand exactly what's happening over the air,

you might want to make use of a Wi-Fi analyzer.

These are analyzers that listen to all

of the signals on this wireless network.

And they're able to provide you with information

about what frequencies are in use and which ones may be open.

This Wi-Fi analyzer might be software

that you would add to a laptop or a mobile device,

or it might be a purpose-built piece of hardware

that's specifically designed to analyze Wi-Fi networks.

This can be very useful if you're

in an area with a lot of Wi-Fi access points,

and allows you to see exactly where interference may

be occurring on this network.

Being able to visually see what's happening on the network

can also help you when you need to make changes.

So if you need to adjust where a Wi-Fi antenna is pointing,

you can make that change and visually see

exactly what the effect of that change might be.

If you've ever worked in a data center or large network

where there are hundreds of different cables

and you just want to find one of those hundreds of cables,

then you probably want to use a tone generator.

Sometimes you'll hear this referred to as a toner

probe, which describes both of the components

that you would use to be able to identify that cable.

One of these is a tone generator that adds

a signal onto the copper wire.

The other is an inductive probe.

This inductive probe doesn't need

to touch the copper that's inside of that cable.

You just need to get close to the cable

so that you can hear the tone that's being generated

on the other end of the cable.

This allows you to easily find where a cable might be,

especially in environments that have hundreds or even

thousands of cables running across the data center.

You would first connect the tone generator

to one end of the wire.

This could be done with a modular jack that's

on the tone generator, or you may

have alligator clips or some other connection type

to that cable.

You would then go to the other end of where this cable is.

It's usually in a large bunch of cables.

And you would use the inductive probe

to move from cable to cable to identify exactly which cable

contains that particular tone.

Let's give this a try.

I've connected a tone generator to one of these four ethernet

cables.

They all look very similar to each other.

So we need to understand exactly which one is connected

to that tone generator.

So now let's use our inductive probe

to be able to find where that tone generator might be.

I'll push the button to turn on the inductive probe.

And I'll simply push it against the outside of this cable.

You can see there's no noise and no light when I push it

against the first cable, the second cable, the third cable.

And then finally, on the last cable

we have a noise and a light that shows

that that's where the tone generator is connected.

In some environments you're not connecting an RJ45 connector,

you're instead connecting to a punch down block.

This is a punch down block.

And you can see that you have a specialized tool that you would

use to connect that wire into the punch

down block permanently.

This can be pretty tedious if you're

working with a lot of cables, because you're

taking each wire that's inside of the cable,

putting each of those wires into their own slot on the punch

down block, and using the punch down tool

to individually fasten those wires to the punch down block.

When you're using this punch down tool,

it's not only pushing the wire into the punch down block,

but it's cutting off any excess wire, making a neat connection

to the block.

When you're working with punch down blocks,

you're usually managing many different cables.

So it's important to have very good organization when you're

using these punch down blocks.

There are usually numbers on each of these punch

down blocks that you can keep track of exactly what cable is

connected to what connection.

Another important characteristic of ethernet

is that we maintain the twist as long

as we can through this cable.

You can see that these cables do maintain a twist all the way

into the punch down block.

It's also good to keep very good documentation.

Each one of these punch down connectors has a number.

And it's useful to duplicate that number

on the other end of the cable.

Another great tool to have in your tool bag

is a cable tester.

These usually come in two different units.

And you plug each one of them into the two ends of the cable.

They'll then perform a continuity test,

and tell you if pin 1 is connected to pin 1,

pin 2 is connected to pin 2, and so on.

Some cable testers can also tell you

if you happen to miss any of these cables

or not punch them down properly or they

may be able to tell you if you crossed

wires between different pins.

These cable testers are relatively simplistic,

and they don't have a lot of advanced functionality.

For example, a cable tester may not

be able to tell you what the crosstalk values might

be between these wires or how much signal loss occurs

from one end of the cable to the other.

For those types of measurements, you'll

need a more advanced tools such as a TDR or Time Domain

Reflectometer.

When you're troubleshooting, it's

useful to know if the problems you're seeing

are related to the cable or related

to the interface on the device.

One way that you could test the interface

is through the use of a loopback plug.

You would have data coming out of an interface,

looping back around, and going right back

into that same device.

This allows you to send information out a serial port,

receive that information immediately back

in that serial port, and be able to compare those two

values to see if they match.

If they don't match then it's very

possible you have a problem with that physical interface.

There are also loopback cables that you

can get for ethernet connections, T1 wide area

network, or fiber connections.

These are not crossover cables, you

can see that you're not connecting multiple devices

together, this is instead used to send data out one interface

and directly back into the same interface.

Crossover cables commonly connect two devices directly

to each other, but a loopback plug is effectively

connecting a device to itself.

When you're troubleshooting a network,

it's sometimes useful to see the data that's

going over the wire itself.

But having access to that data can be problematic.

One way that you could see the data on that connection

is with a physical network tap.

This allows you to disconnect a link,

put our physical tap in the middle,

and take a copy of all of that data

and send it to an analyzer.

This might be a passive tap that doesn't require fiber.

We commonly see that with fiber taps.

Or it might be an active tap that

is able to tap copper connections

but requires power to be able to do that.

If you don't have a physical tap,

you may be able to use a tapping function that's

built into your switch.

This is called a port mirror or a SPAN.

The SPAN is an abbreviation for Switched Port Analyzer.

This is a function built into the switch that's

able to take data that's going between different interfaces

on the switch and send a copy of that data to a third interface

that you can then connect to an analyzer.

There are obviously resource limitations

in the switch and bandwidth limitations

on the interfaces themselves.

But if you need something very simple

that can be used temporarily, a switch port analyzer or port

mirror is a perfect solution.

Looking closer at this physical tap,

you can start to see how this tap operates

based on the design that's on the outside.

Physically, you can see that we would

break the connection between two devices

and put this tap in the middle.

And since we have another cable between those devices going

the other direction, we would break that connection

and put the tap between that one as well.

Now that we've completed this circuit,

everything continues to flow between these two devices,

but the tap is going to create a copy of that data

and send it out to additional interfaces on this tap.

You can then plug in a protocol analyzer or any type of monitor

to be able to see all of the traffic that's

traversing these two devices.