MODULE 2

Question 1

It is an interconnected set of autonomous computers.

Answer 1

Computer Network

Question 2

Computer networks have emerged as a result of the convergence of two technologies of this century

Answer 2

Computer and Communication

Question 3

The exchange of data between two nodes (e.g., computer) via some form of transmission media (e.g., cable).

Answer 3

Data Communication

Question 4

3 types of data flow

Answer 4

✓ Simplex
✓ Half Duplex
✓ Full Duplex

Question 5

In this case data flows in only one direction on the data communication line (medium).

Answer 5

Simplex

Question 6

Data flows in both directions but not at the same time. If one device is sending, the other can only receive (vice versa).

Answer 6

Half Duplex

Question 7

Data flows in both directions simultaneously. Device can send and receive at the same time.

Answer 7

Full Duplex

Question 8

It is a set of rules that govern data communication.

Answer 8

Protocol

Question 9

Protocol used in network communications also define:

Answer 9

✓ Message Encoding
✓ Message Formatting and encapsulation
✓ Message timing
✓ Message size
✓ Message delivery options

Question 10

Illustration of message encoding:

Answer 10

Message source – Encoder (Signal) – Transmitter – Transmitter Medium – Receiver - Decoder (Signal) - Message Destination

Question 11

Both sender and receiver must agree upon a format.

Answer 11

Message Formatting

Question 12

The process in which some extra information is added to the data item to identify the sender and receiver.

Answer 12

Data Encapsulation

Question 13

Long messages must be broken into smaller pieces to travel across a network so that the transmission medium can handle it.

Answer 13

Message Size

Question 14

3 Types of Message Delivery Options

Answer 14

✓ Unicast
✓ Multicast
✓ Broadcast

Question 15

2 Types of Transmission Network

Answer 15

✓ Broadcast Network
✓ Point-to-point Network

Question 16

It has a single communication channel that is shared by all the machines on the network.

Answer 16

Broadcast Networks

Question 17

This system generally also
allows possibility of addressing
the packet to all destinations (all nodes on the network). When
such a packet is transmitted
and received by all the
machines on the network, this mode of operation is known as ___ .

Answer 17

Broadcast Mode

Question 18

Some Broadcast systems also supports transmission to a sub-set of machines, something
known as ___ .

Answer 18

Multicasting

Question 19

The end devices that wish to communicate are called stations.The switching devices are called nodes. Some nodes connect to other nodes and some attached stations. There may exist multiple paths between a source-destination pair for better network reliability. The switching nodes are not concerned with the contents of data.

Answer 19

Point-to-point Networks

Question 20

As a general rule (although there are many exceptions),smaller, geographically localized networks tend to use ___, whereas larger networks normally use are ___ .

Answer 20

✓ Broadcasting
✓ Point-to-point Communication

Question 21

3 Types of Network under Scale:

Answer 21

✓ Local Area Network (LAN)
✓ Metropolitan Area Network (MAN)
✓ Wide Area Network (WAN)

Question 22

It is usually privately owned and links the devices in a single office, building or campus of up to few kilometers in size.

Answer 22

Local Area Network (LAN)

Question 23

It is designed to extend over the entire city. It may be a single network as a cable TV network or it may be means of connecting a number of LANs into a larger network so that resources may be shared.

Answer 23

Metropolitan Area Network (MAN)

Question 24

This provides long distance transmission of data, voice, image, and information over large geographical areas that may comprise a country, continent, or even the whole world.

Answer 24

Wide Area Network (WAN)

Question 25

In computer networking, ___ refers to the layout of connected devices. It is the physical connection of wires that connect nodes of the network.

Answer 25

Topology

Question 26

Types of Network Topology

Answer 26

✓ Linear Bus Topology ✓ Star Topology ✓ Ring Topology ✓ Hybrid Topology

Question 27

A single cable, the backbone functions as a shared communication medium that devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.

Answer 27

Bus Topology

Question 28

In this type of network topology, the server(s), nodes and other hardware devices are connected to a central hub. All messages and data from the source node must first pass through the central hub before it can reach the target node. The hub is responsible for preventing data collision.

Answer 28

Star Topology

Question 29

In this type of network topology, the server(s), the nodes and other hardware devices are connected in a circular chain where each node is connected to the next. The last node to be connected is connected to the first node which forms a ring. So, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either clockwise or counterclockwise) until it reaches a target node.

Answer 29

Ring Topology

Question 30

In this type of network topology, the other types of topologies are combined to form a combination or hybrid network topology. Hybrid topologies are usually used to connect different floors or rooms of a building.

Answer 30

Hybrid Topology

Question 31

Defined as the physical path between transmitter and receiver in a data transmission system.

Answer 31

Transmission Media

Question 32

2 Types of Transmission Media

Answer 32

✓ Guided ✓ Unguided

Question 33

Transmission capacity depends critically on the medium, the length, and whether the medium is point-to-point or multipoint (e.g. LAN).

Answer 33

Guided

Question 34

This provides a means for transmitting electro-magnetic signals but do not guide them.

Answer 34

Unguided

Question 35

In ___ technology, two copper wires are strung between two points. The two wires are typically twisted together in a helix to reduce interference between the two conductors. Twisting decreases the cross-talk interference between adjacent pairs in a cable. Typically, a number of pairs are bundled together into a cable by wrapping them in a tough protective sheath.

Answer 35

Twisted Pair

Question 36

2 Types of Twisted Pair

Answer 36

✓ Unshielded Twisted-Pair (UTB) cables ✓ Shielded Twisted-Pair (STB) cables

Question 37

Typically wrapped inside a plastic cover (for mechanical protection).

Answer 37

Unshielded Twisted-Pair (UTP)

Question 38

These cables are similar to UTP cables, except there is a metal foil or braided-metal-mesh cover that encases each pair of insulated wire.

Answer 38

Shielded Twisted-Pair (STP)

Question 39

In this type of guided transmission media, the medium consists of a copper core surrounded by insulating material and a braided outer conductor.

Answer 39

Coaxial

Question 40

2 Types of Coaxial Cable

Answer 40

✓ Base Band ✓ Broadband

Question 41

This refers to digital transmission.

Answer 41

Base band

Question 42

This refers to analog transmission.

Answer 42

Broadband

Question 43

In this type of guided transmission media, the medium consists of a hair-width strand of silicon or glass, and the signal consists of pulses of light. For instance, a pulse of light means 1, lack of pulse means 0. It has a cylindrical shape and consists of three concentric sections: the core, the cladding, and the jacket.

Answer 43

Fiber Optics

Question 44

This is used when running a physical cable (either fiber or copper) between two endpoints is not possible.

Answer 44

Unguided Transmission

Question 45

___ are typically used for short distances (across the street or within the same room), and microwave signals are commonly used for longer distances (tens of km). The sender and receiver use some sort of dish antenna.

Answer 45

Infrared Signals

Question 46

This is based on ideas similar to those used for line-of-sight. It is essentially a big microwave repeater or relay station in the sky. Microwave signals from a ground station is picked up by a transponder, it then amplifies the signal and rebroadcasts it in another frequency, which can be received by ground stations at long distances.

Answer 46

Satellite Communication