Csc 206 (Intro To Computer Networks)

Question 1

What is a computer network

Answer 1

A computer network is a system of interconnected computers or other devices thats can communicate with each other and share resources data and information

Question 2

Technologies that can be used to establish various networks

Answer 2

Wired or wireless connections

Question 3

PImportance of computer networks

Answer 3

1) to aid communication- networks enables communication among individuals and organizations.

2) resource sharing- networks allows for the sharing of hard ware resources such as printer and scanner as well as soft ware resources such as applications and data bases

3) data exchange - networks facilitated the exchange of data and information between connected devices enabling seamless data transfer and access to information regardless of the location

4) business operations- network play a vital role in modern businesses allowing e-commerce, online banking, inventory management, supple chain co- ordination etc

5) access to information: computer networks provides access to vast storage of information available on the internet and other network resources

5) entertainment and media-
Network provides a platform for entertainment allowing the streaming of videos, music and games to users worldwide

6) remote access and mobility -network allows remote access to resources and services allowing users to work from anywhere using a computer smartphone or other connected devices

Question 4

List the types of networks we have and explain

Answer 4

1) pan - personal area networks is the smallest and most personal type of network, connecting devices within the immediate environment of the individual user. Pan technology include Bluetooth Wi-Fi infra-red

2) lan- local area network cavers a small geographical area like a single building, office and campus. It uses high speed Ethernet or Wi-Fi connections to interconnect computers, servers and other devices.

3) man - metropolitan area network covers a larger geographical area than the lan but a smaller area than the wan. It is used to interconnect multiple lan within a city or neighboring cities providing high speed connectivity for businesses, educational institutions and government agencies. The technology used in man are fiber optics, Ethernet and wireless connections

4) wan - wide area network covers a larger geographical area than man, its connects multiple lan and other networks over a long distance. The technologies used are leased lines, satellite links, fiber optics and wireless connections.

Question 5

What is network topology

Answer 5

Network topologies defines the physical and logical layout of interconnected devices in a network

Question 6

Types of network topology

Answer 6

1) bus
2) star
3) ring
4) mesh

Question 7

Explain bus list advantages and disadvantages with diagram

Answer 7

For bus all the devices are connected in a single communication channel. The devices communicate by sending data on the bus, it is then received by all the devices in the network

Advantage
1) it is simple and inexpensive
2) is is suitable for small networks with little devices

Disadvantage
1) limited scalability as adding more devices will cause congestion
2) it can fail ,if the bus is damaged the entire system will fail

Question 8

Explain star list the advantages and disadvantages

Answer 8

In the star topology , every device is connected to a central hub/switch. Communication between devices must pass through the central hub/switch

Advantages
1) it is scalable and devices can be added or removed without affecting the entire network
2) fail tolerant I.e if on device fail it doesn’t affect the entire system

Disadvantage
1) over reliance on the central hub/ switch, if it fails it may affect the entire network
2) it is expensive to implement

Question 9

Explain ring list the advantages and disadvantages

Answer 9

In ring topology each device is connected to exactly two other devices to form a closed loop or ring. Data travels around the ring in one direction passing through each device until it reaches its destination

Advantages
1) it is simple and easy to implement
2) doesn’t require a central hub, thereby reducing cost

Disadvantage
1) single point of failure
2) difficult to troubleshoot and identify faults

Question 10

Explain mesh list the advantages and disadvantages

Answer 10

In a mesh topology, each device is connected to every other device in the network. Forming a fully interconnected mesh of network. Mesh network can be full mesh or partial mesh

Advantages
1) it is high fault tolerant
2) it is a scalable and can support large network with large traffic volumes

Disadvantage
1) it is complex and expensive to implement and maintain
2) it requires significant cabling and software resources.

Question 11

Factors to consider when choosing a network topology

Answer 11

1) performance of the network
2) cost of implementation
3) scalability
4) fault tolerance

Question 12

What are network models and the types

Answer 12

Network models provides a framework for communication between devices in a network, outlining each layer of communication and the protocol used within each layer.

Types
1) open system interconnection (OSI) model
2) Transmission Control Protocol/ internet protocol (TCP/ip)

Question 13

What is osi model and who mad it and when

Answer 13

The open system interconnection is a conceptual framework that standardize and conceptualize the functions of telecommunication and network systems
It was created by the international organization of standardization in the 1980

Question 14

List and explain the 7 layers off the OSI model

Answer 14

1) physical layer - this layer deals with the physical transmission of data over the communication medium such as cables, fiber optic and wireless signals . Example of physical layer standard is the Wi-Fi and Ethernet

2) data link layer - this layer provides reliable point-to-point and point-to-multiple point communication between devices on the same network segment. Example of standard are Ethernet Wi-Fi and point-to-point protocol (PPP)

3)network layer - is responsible for routing and forwarding packets between different networks or subnetworks. It determines the optimal path for data transmission based on network topology, adressing and routing algorithm. The primary protocol is the Internet protocol (IP)

4) transport layer - this layer ensure reliable end-to-end communication between hosts, provides error detection and recovery mechanisms. It segments and reassemble data from upper layers, handles, flow control and manages end to end connections. protocols are user Datagram protocol (UDP), Transmission Control Protocol (TCP)

5) session layer: this layer is responsible for establishing, maintaining, and terminating sessions between different applications in multiple devices. It is responsible for session synchronization and recovery mechanisms. Protocol is session initiation protocol (SIP)

6) presentation layer: it formats data for presentation to the application layer. It is responsible for data translation, encryption and compression to ensure compatibility between different systems. Protocols are multipurpose internet mail extension (MIME), secure socket layer/ transport layer security

7) application layer - it provides network services directly to the end users and applications. It supports application level protocol for task such as file transfer, email, remote access and web browsing

Question 15

What is tcp/ip model

Answer 15

The Transmission Control Protocol/ internet control model is a conceptual framework that describes the standard and protocols that govern communication over the internet and computer networks.

Question 16

List and explain the 4 layers of the tcp/ip model

Answer 16

1)link layer- its is responsible for transmitting data between different devices on the same physical network segment. It combines the function of both the physical and datalink layer off the osi model. Protocol as are the Ethernet ppp, wi-fi

2) internet layer - this corresponds with the network layer of the osi model and provides logical addressing. It is responsible for the rousing and forwarding of packets between different devices

3)transport layer- this layer is responsible for end-to-end communication between hosts and reliable data delivery. Protocol are udp and tcp

4) application layer- this layer provides network services directly to the end user and application. It corresponds directly to the session, presentation and application layer of the osi model and supports various application level protocols. Examples HTTP for web browsing, SMTP (simple mail transfer protocol) for email), ftp (file transfer protocol), DNS ( domain name system)

Question 17

Network protocol

Answer 17

Network protocol are a set of rules that govern communication and data transfer between devices on a network

Question 18

What is a transmission media and give the types

Answer 18

This is a digital pathway through which data is transmitted in a network. It plays a crucial role in determining the performance,
Scalability and reliability of a communications network.

Types
. Guided
. Unguided

Question 19

Explain guided transmission media and list examples

Answer 19

They are physical cables or wire that provide a direct tangible pathway for transmitting data eg twisted pair cables, coaxial cable, fiber optic cables.

Question 20

Write on twisted pair cable with its advantages and disadvantages

Answer 20

It consists of a pair of insulated copper wires twisted together. It is widely used in short to medium distance communication and is suitable for internet, networking, telephone lines, and LAN

Advantage- it is cost effective

Disadvantage- it is susceptible to electromagnetic interference and cross talk especially in areas with high electrical noise

Question 21

Write on coaxial cable with advantages and disadvantages

Answer 21

It consists of a central conductor surrounded by an insulator, a metallic shield, and an outer insulating layer. It provers a higher bandwidth compared to the twisted pair and covers a longer distance.

Advantages
1) provides better shielding
2) less susceptible to electromagnetic interference and cross talk
3 it is mostly used in cable tv, broad band internet and high speed data network

Disadvantage
1) it is limited by distance

Question 22

Write on fiber optic cables and give advantages and disadvantages

Answer 22

It transmits data using light signals through a glass/ plastic tube surrounded by a cladding material

Advantages
1) it provides a high bandwidth
2) it is resistant to emi making suitable for long distance communication and high speed data transmission
3) it provides more secure transmission as it is difficult to intercept without physical contact with the cable
4) it is highly resistant to environmental factors
5) it is used I. Telecommunication networks, internet backbone infrastructure, high performance computing environments

Question 23

What is unguided transmission media and give examples

Answer 23

It transmits data signals through the air without the need for physical cable and connection

Examples- microwave, radio wave, infrared wave

Question 24

Write on Radio wave

Answer 24

This allows data signals to be transmitted through the atmosphere and can be affected by hot cable interference and environmental conclusions

It is used in wireless communication like Wi-Fi blue tooth and cellular networks

Question 25

Write on microwave

Answer 25

This is employed for point to point communication over long distances. It is used in satellite communications, microwave radio relay systems, raider applications

Question 26

Write on infrared

Answer 26

This is utilized in short range communication systems such as between devices like remote control and smart devices/ phone . It is limited by line of sight and susceptibility to interference from othe light sources

Question 27

Factors influencing media selection

Answer 27

. Bandwidth . Distance . Cost . Scalability and future expansion . Installation and maintenance . Environmental factors . Security and privacy

Question 28

What is transmission mode

Answer 28

It is defined as the various ways or techniques for transmitting data over a channel

Question 29

What defines a transmission mode

Answer 29

1) direction of exchange or data flow 2) the data of bits sent 3) synchronization between devices

Question 30

List types of transmission mode based on direction of exchange

Answer 30

1* simplex 2* half duplex 3* full duplex

Question 31

Explain half duplex and list its advantages and disadvantages

Answer 31

In this mode data flows in both direction but not simultaneously ie devices transmit and receive data but not at the same time eg walkie talkie ADVANTAGE 1) more flexible than simplex as it allows bidirectional communication 2) it required less bandwidth than full duplex DISADVANTAGES 1)it is not suitable for real time continuous communication as devices must alternate between transmitting and retrieving 2) increased complexity due to the need for mechanism to manage data flow and event collisions

Question 32

Explain simplex and list its advantages and disadvantages

Answer 32

In this mode data flows from one direction from the transmitter to the receiver I.e communication is unidirectional ADVANTAGE 1) it is straightforward and requires minimal hardware complexity 2) it is suitable for applications that does not require feedback or response from the user

Question 33

Explain full duplex and list its advantages and disadvantages

Answer 33

In this mode data can flow simultaneously in both directions allowing devices to transmit and receive data concurrently eg telephone conversations, video conferencing systems and internet networks ADVANTAGE 1) it provides the highest level flexibility and efficiency 2) it enables real-time interactive communication without the need to wait for turns DISADVANTAGE 1) it requires more sophisticated hardware and protocol to manage simultaneous data transmission and reception 2) it requires more bandwidth than half duplex and simplex

Question 34

Types of transmission mode based on number of bits sent

Answer 34

Serial transmission- each bit representing data is sent one after the other in a sequence in a single channel 2)parallel transmission- group of bits or bytes are transmitted simultaneously across multiple lines

Question 35

List and explain type of transmission mode based on synchronization

Answer 35

1) synchronized transmission- data is sent as blocks or frames. It is full Duplex in nature and requires synchronization between the sender and receiver. This is achieved using a clock signal to ensure the sender and receiver operate at the same speed eg telephone communication video streaming 2) asynchronous transmission- in this mode data is sent in form of bits or characters. It is a half duplex transmission that allows start bits and stop bits to be added to the data and does not require synchronization

Question 36

Explain various network devices

Answer 36

1) routers - this is a network device that connects multiple computer networks and direct data traffic between them . It works by using up addresses to determine the best path for forwarding data packets to their destination 2) switches- it is used to connect multiple devices to a LAN and manage data traffic efficiently. It work by using MA address to forward data to the specific device it is intended for ( full duplex) 3) Hubs - it is used to connect multiple devices within a LAN and broadcast data to all of them . It does not differentiate between devices every signal received is sent to all connected devices ( Haley duplex) 4) bridges - a network device that connects and filter traffic between two or more networks segment and make function as a single network . They work by analyzing MAC addresses and determine wether to block or forward traffic 5) gateway - network device used to connect two or more separate networks that may have different protocols or architecture allowing them to communicate with each other . It works by translating data from one protocol to another so networks can communicate 6) network interfaces card - it is a hardware component installed in a computer or device that allows it to connect to a network. It provides a hardware interface between the computer and the network cable or wireless signal