The physical network

Unit objective: Identify network cables and

connectors, and use networking tools

Topic A

Topic A: Network cable and connector types

Topic B: Cable and connector properties

Topic C: Networking tools

Fiber optic cable Carries light-based data Strands of glass or plastic Components

contnued

Fiber optic connectors

ST SC LC Other connectors

Twisted-pair cable

Copper wire Unshielded twisted-pair Shielded twisted-pair Connectors

– RJ-45– RJ-11

Coaxial cable

Found in older networks

continued

Coaxial cable, continued

RG-8 and RG-58 used in Ethernet

RG = Radio Guide Stranded or solid Impedance in ohms,

Ω Thicknet cables are

RG-8 Thin Ethernet cables

are RG-58

Topic B

Topic A: Network cable and connector types

Topic B: Cable and connector properties

Topic C: Networking tools

Fiber optic cable Two types

– Single-mode– Multimode

Commonly used for long distances and backbones Benefits:

– Thinner and lighter weight – Higher carrying capacity – Use of digital signals – Less signal degradation – Less interference – Non-flammable – More secure

Common UTP categories

Category Speed and frequency Typical use

CAT 3 10 Mbps; 16 MHz Voice in newer telephone systems.

The minimum category you can use for data networks. Most often found in 10BASE-T networks.

Ethernet, Fast Ethernet, and Token Ring all support CAT 3.

CAT 5 100 Mbps; 100 MHz

155 Mbps ATM

Used for data and voice in Ethernet networks running at 10 or 100 Mbps.

Ethernet, Fast Ethernet, Gigabit Ethernet, Token Ring, and ATM all support CAT 5.

CAT 5e 100 Mbps; 100 MHz

155 Mbps ATM

Used for data and voice in Fast Ethernet and Gigabit Ethernet networks. Has better transmission performance characteristics than CAT 5.

Ethernet, Fast Ethernet, Gigabit Ethernet, Token Ring, and ATM all support CAT 5e.

CAT 6 1 Gbps; 250 MHz

155 Mbps ATM

Used for data in Fast Ethernet and Gigabit Ethernet networks.

Ethernet, Fast Ethernet, Gigabit Ethernet, Token Ring, and ATM all support CAT 6.

Additional TP categories

Stranded vs. solid

Solid – Thicker, more protective covering – Less flexible– Best for longer network runs and fixed

wiring

Stranded – Thinner protective covering– More pliable – Useful for shorter-distances and movable

wiring

Straight-through and cross-over

Straight-through– TP cable; both ends follow either 568A or 568B– Used to connect computers to hub or switch

Cross-over – TP cable; one end is wired using 568A, and the

other using 568B – Used to connect two computers together

Pin numbering of RJ-45 connector

T1 crossover cable

Connects two T1 devices together without a network device between them

Cable end 1 Cable end 2

Pin 1 Pin 4

Pin 2 Pin 5

Pin 4 Pin 1

Pin 5 Pin 2

RG standards

Standard Impedance Core size Uses

RG-6/U 75 1.0 mm Cable and satellite television; cable modems

RG-6/UQ 75 1.0 mm Q stands for quad: 4 layers of shielding, compared to RG-6/U, which has 2.

RG-8/U 50 2.17 mm Thicknet network backbones; amateur radio.

RG-9/U 51 2.17 mm Thicknet network backbones

RG-11/U 75 1.63 mm Cable and satellite television, video surveillance; thicker than RG-6. Used underground or for outdoor antennae drops.

RG-58/U 50 0.9 mm Thin Ethernet; radio; amateur radio.

RG-59/U 75 0.81 mm Baseband video in closed-circuit television; cable television.

RG standards

Standard Impedance Core size Uses

RG-6/U 75 1.0 mm Cable and satellite television; cable modems

RG-6/UQ 75 1.0 mm Q stands for quad: 4 layers of shielding, compared to RG-6/U, which has 2.

RG-8/U 50 2.17 mm Thicknet network backbones; amateur radio.

RG-9/U 51 2.17 mm Thicknet network backbones

RG-11/U 75 1.63 mm Cable and satellite television, video surveillance; thicker than RG-6. Used underground or for outdoor antennae drops.

RG-58/U 50 0.9 mm Thin Ethernet; radio; amateur radio.

RG-59/U 75 0.81 mm Baseband video in closed-circuit television; cable television.

Topic C

Topic A: Network cable and connector types

Topic B: Cable and connector properties

Topic C: Networking tools

Crimper

Coax crimper

Terminating a coaxial Thinnet cable to a BNC connector

Twisted-pair cable crimper

Punchdown tool

Using a punchdown tool

1. Insert the wire between the two metal blades on the punchdown block. There is one wire per contact in the punchdown block.

2. Place the punchdown tool on top of the wire. (Remember to have the correct side of the tool facing up.)

3. Apply pressure to the wire until you hear a snap. This snap is from the spring mechanism inside the tool.

Cable testing device

Test physical cables and network functions

Single LAN type device or multiple LAN type device

Physical cable tests

Locating incorrectly wired cables, open cables, and shorts

Locating missing cables Locating cables that don’t support your

network type Testing hub connections Testing PC connections Testing installed cables Testing patch cables Locating and tracing inactive cables

Network function tests Verifying that a PC or switch is powered on Specifying whether a device is a network PC or a

switch Displaying the maximum network connection speed

to the device Verifying PC-to-switch speed, and data

transmission and port speed or duplex mismatch Verifying switch-to-switch data transmission Determining if a straight-through or crossover patch

cable is required Finding speed bottlenecks on LANs Monitoring a LAN link between two devices

Toner probe

Amplifier probe Locate, identify, and trace wires or

cables Works with a tone generator

Using a tone probe

1. Set the tone generator to tone.

2. Test the tone generator.

3. Connect the tone generator to one end of the cable you want to trace.

4. Use the probe to identify where the cable comes into your patch panel or 110 block. Move to the cable bundle and identify the cable in the bundle that runs to where you’ve connected the tone generator.

5. Disconnect the tone generator and turn it off.

Loopback plug

Test ports Specific to type of

port Ethernet loopback

– 10 and 100 Mbps– Gigabit

Network loopback plug - can make your own or buy commercial

Multimeters

Use to measure electricity from power supply or computer component

Available in digital and analog models

Measuring resistance

1. Turn off the device you’re measuring and disconnect it from its power source

2. If necessary disconnect the device from its circuit

3. Set the multimeter to read resistance

4. Touch the two leads of the multimeter together

5. Touch the black and red probes to either side of the circuit to be measured, and read the resistance from the meter’s display

Measuring voltage

1. The power supply must be on

2. Set your multimeter to read either DC or AC voltage

3. Touch the black probe to the ground, and touch the red probe to the spot where you want to measure the voltage

Measuring current

1. Break the circuit

2. Insert the meter in the break

3. Read the current flowing through circuit

Can also use an ammeter or clamp-ion ammeter to measure current flow

Measuring continuity

1. Set multimeter to display resistance

2. Look for circuits with zero resistance If your multimeter includes a continuity

mode, you can use that. In continuity mode, multimeter sounds

a tone whenever it detects a closed circuit

Unit summary

Identified network cables and connectors, and used networking tools