Chapter 4 - Conducted and Wireless Media

Question 1

Twisted Pair Wire

Answer 1

• Copper and pair of wires is twisted together.
• Consists of 4 pairs of twisted conductors
• Most common choice of network cable
• Can be labeled as:
- Unshielded twisted pair (UTP)
- Shielded twisted pair (STP)
~ Shielding protects against crosstalk and outside sources of interference
• Data transmission speed:
- 9600 bits per second
~ Distance of 100 meters
• Category 1 through 7 (Uses category 6/7)

Question 2

Network Media

Answer 2

Network media is the actual path over which an electrical signal travels as it move from one component to another.

Question 3

Advantages of twisted pair cables

Answer 3

• Twisted pair cables are the most commonly used networking cables on the market and are considered to be the fastest copper-based medium
• Price affordable
• STP cables are easier to work with during installation

Question 4

Disadvantages of twisted pair cables

Answer 4

• The cables are more prone to electronic noise and interference
• The distance between the signal boosts is shorter. (Max 100m). Making it less able to carry the signal for long-distance networking

Question 5

Why twisted pair wire is twisted?

Answer 5

• Twisted together for the purpose of cancelling out electromagnetic interference (EMI)
• To prevent crosstalk

Question 6

Coaxial cable

Answer 6

• groups of specially wrapped and insulated wires that are able to transfer data at higher rate.
• Consists of:
- A central copper
~ Surrounded by an insulation over which the copper mesh is placed
- Insulator is covered with a shield
~ Shield is made of other solid foil or braided wire
• Used for:
- Long distance telephone lines
- Local area network

Question 7

Advantages of coaxial cable

Answer 7

• capable of transmitting different types of signals
• coaxial cable are typically protected by thick layers of rubber(outer jacket)
• More resistant to interference

Question 8

Disadvantages of coaxial cable

Answer 8

• Coaxial cable is thick, it does not bend easily

* This installation of the coaxial cable might be difficult

Question 9

Fiber-Optic Cable

Answer 9

• A thin glass cable approximately a little thicker than a human hair surrounded by a plastic coating and packaged into an insulated cable
• It supports transmission rates over 1Gpbs
• It is primarily used for network backbones and long distance runs
• Components:
	- Fiber optic cable
	- Jacket
	- Fire resistant yarn
• Transmission rates:
	- 1+ Gbps
• Primarily used for:
	- Network backbones
	 	~ Between cities
	 	~ Between buildings
	- Long distance runs

Question 10

Advantages of fiber-optic cable

Answer 10

• Bandwidth - Fiber optic cable have a much greater bandwidth than metal cables. The amount of information that can be transmitted per unit time of fiber over than transmission media is its most significant advantage
• Low power loss - This allows for longer transmission distance. In comparison to copper; in a network, the longest recommended copper distance is 100m while with fiber, it is 2000m
• Interference - fiber optic cables are immune to electromagnetic interference. It can also be run in electrically noisy environment without concern as electrical noise will not effect fiber.

Question 11

Disadvantages of fiber-optic cable

Answer 11

• Cost - Cables are expensive to install but last longer than copper cables
• Fragile - glass can be easily broken
• Protection - optical fiber require more protection around the cable compared to copper

Question 12

Microwave

Answer 12

• Uses very high frequency radio signals
	- Transmit data through space
• Transmitter and receiver:
	- Should be in line-of-sight
	 	~ Radio signal cannot bend
• Long distance transmission is not possible

Question 13

Attenuation

Answer 13

• a general term that refers to any reduction in the strength of signal
• also called as loss
• Range:
- Wireless and wired transmission gradually dissipate in strength over longer reaches
• Interference:
- On wireless networks, radio interference or physical obstructions like walls also reduce communication signals

Question 14

Communication satellite

Answer 14

• overcome the problem of line-sight and repeaters

* The satellite amplifies the weak signal and transmits it back to the receiver.

Question 15

Cellular telephones

Answer 15

• based on radio waves connecting to designated areas referred to as cells
• a remote device connects to a radio transmitter/receiver within its cell
• The radio transmitter/receiver communicates to remote cells via microwave transmission or telephone lines.

Question 16

Advantages of cellular network

Answer 16

• Faster data transfer speed (4G)
• For video chat and references
• You can easily stream music and videos

Question 17

Disadvantages of cellular network

Answer 17

• Coverage area - Only available at larger city
• Mobile networks use multiple antennae and transmitters and hence, users would experience much poorer battery life on their mobile devices, while on this network.

Question 18

Advantages of wireless broadband

Answer 18

• Users can move around freely within the area of the network with their laptops, handheld devices etc and get and internet connection.
• Not having to lay lots of cables and put them through walls etc.
• Wireless networks can sometimes handle a larger amount of users because they are not limited by a specific number of connection parts

Question 19

Disadvantages of wireless broadband

Answer 19

• Wireless connections can be obstructed by everyday household items and structures such as walls, ceilings, and furniture.
• Wireless network are generally less secure. There can also be problems with neighbors stealing bandwidth, if the network hasn’t been set up to be password protected. Information is also loss secure too and can be easier to hack into.

Question 20

Wireless access point (WAP)

Answer 20

• It provides a connection between a wireless network and a cable based network.
• provides access from wireless network devices to needed hardwired network devices such as printers, modems and routers

Question 21

Media selection criteria

Answer 21

• Cost
	- Effective costs
	 	~ Initial setup
	 	~ Supporting cost (devices)
	 	~ Installation cost

• Speed
- Data transmission speed

• Distance and expandability
- Coverage
~ UTP cable = 100 meters max

• Environment
- Heavy machinery
~ Produces electromagnetic interference that can interfere with the cables

• Security
- Physical or wireless access control

Question 22

Network Path

Answer 22

• An actual path over which an electrical signal travels as it moves from one component to another
• Examples:
	- Twisted pair cable
	- Coaxial cable
	- Fiber-optic cable
	- Wireless

Question 23

Advantages of Communication Satellite

Answer 23

• A single microwave relay station visible from any point of a very large area
• Wide coverage
• Fast transmission speed:
- 16 gigabits per second (Gbps)
• Useful for users who are located in remote areas and cannot access broadcast connection

Question 24

Broadband Wireless Systems

Answer 24

• Designed for home or business use
- Consists of two or more computers with wireless adapters
• Fast and easily installation with no wires
• Delivers internet services into homes and businesses
• Bypasses the local loop telephone line
• High frequency radio signals transmission
• Wi-Max:
- IEEE 802.16 standard
- 300 kbps to 2Mbps over a range of as much as 30 miles