Basic Network Media

Week 3

Objectives

• We examined the nature of a network

• General terms were introduced that describe what networks are, how they are structured, and how they can benefit us

• The physical aspects of a network to learn about the cables and circuitry that connect one computer to another.

Network Cabling

Network cabling acts as network transmission medium that carries signals between computers.

Primary Cable Types. Three major groups of cabling connect the majority of networks.

• Coaxial cable

• Twisted-pair (unshielded and shielded) cable

• Fiber-optic cable

Coaxial Cable

• Coaxial cable was the most widely used network cabling.

• It was relatively inexpensive, light, flexible, and easy to work with.

• Coaxial cable consists of a core of copper wire surrounded by insulation, a braided metal shielding, and an outer cover.

• Shielding protects transmitted data by absorbing stray electronic signals, called noise, so that they do not onto the cable and distort the data.

• There are two Types of Coaxial Cable:

1. Thinnet cable

2. Thicknet cable

1. Thinnet cable. Is a flexible coaxial cable about 0.64 centimeters (0.25 inches) thick

•This type of coaxial cable is flexible and easy to work with, it can be used in almost any type of network installation.

•Thinnet cable connected directly to a computer’s network interface card (NIC).

• Can carry a signal for a distance of up to approximately 185 meters (about 607 feet) before the signal starts to suffer from attenuation.

Close-up view of thinnet cable showing where it connects to a computer

Attenuation causes signals to deteriorate

List cable types and description

• Cable manufacturers have agreed upon specific designations for different types of cable.

Cable Description

RG-58/U solid copper core

RG-58 A/U stranded wire core

2. Thicknet cable. Is a relatively rigid coaxial cable about 1.27 centimeter (0.5 inches) in diameter.

• Thicknet cable is sometimes referred to as Standard Ethernet because it was the first type of cable used with the popular network architecture Ethernet.

• Can carry a signal for 500 meters (about 1640 feet).

• Thick cable does not bend easily and is, therefore, harder to install.

• Thick cable is more expensive but will carry a signal farther.

Coaxial-Cable Connection Hardware

• Both thinnet and thicknet use a connection component, known as a BNC connector, to make the connection between the cable and the computers. There are several important components in the BNC family:

1. The BNC cable connector. Either soldered or crimped to the end of a cable.

2. The BNC T connector. To joins the NIC in the computer to the network cable.

3. The BNC barrel connector. To join two length to make one longer length.

4. The BNC terminator. Closes each end of the bus cable to absorb stray signals.

Twisted-Pair Cable

• Twisted-pair cable consists of two insulated strands of copper wire twisted around each other.

• There are two types of twisted-pair cable: unshielded twisted-pair (UTP) and shielded twisted-pair (STP) cable.

Unshielded Twisted-Pair (UTP) Cable

• UTP, using 10BaseT specification, is the most popular type of twisted-pair cable and is fast becoming the most popular LAN cabling.

• The maximum cable length segment is 100 meters, about 328 feet.• These standard include five categories of UTP.

– Category 1. telephone cable that can carry voice but not data transmission

– Category 2. for data transmission up to 4 megabytes per second (Mbps). It consists of four twisted pairs of copper wire.

– Category 3. for data transmission up to 16 Mbps. It consists of four twisted pairs of copper wire.

– Category 4. data transmission up to 20 Mbps. It consists of four twisted pairs of copper wire.

– Category 5. data transmission up to 100 Mbps. It consists of four twisted pairs of copper wire.

Twisted-Pair Cabling Components

• Distribution racks and rack shelves

• Expandable patch panels

• Jack couplers

• Wall plates

Fiber-Optic Cable• Optical fibers carry digital data signals in the form of

modulated pulses of light.

• No electrical impulses are carried over the fiber-optic cable. This means that fiber-optic cable cannot be tapped, and its data cannot be stolen.

• Fiber-optic cable is good for very high-speed, high-capacity data transmission because of the purity of the signal and lack of signal attenuation.

• Fiber-optic cable transmissions are not subject to electrical interference.

Quiz: ¼ yellow paper

1. Thinnet cable can carry a signal for a distance of about 185 meters (607 feet) before the signal starts to suffer from __________________.

2. The most popular type of twisted-pair cable is _______.

3. UTP cable for data transmissions up to 10 Mbps is category ______.

4. UTP cable for data transmissions up to 100 Mbps is category _____.

5. Optical fibers carry _______________ data signals in the form of light pulses.

6. Fiber-optic cable cannot be ____________________, and the data cannot be stolen.

7. Fiber-optic cable transmissions are not subject to electrical ________.

8. A Coaxial connector joins the NIC in the computer to the network cable.

9. A Coaxial connector join two length to make one longer length.

10. Acts as transmission medium that carries signals between computers.

end

1. Attenuation2. UTP3. 34. 55. Digital6. Tapped7. Interference8. BNC T connector9. BNC barrel connector10. Network Cabling