Introduction To Computer Network Question And Answer | letsbug

Introduction To Computer Network 

1.  Answer the following questions in short.

1. Define Computer Network.

    Answer: 

    A computer network is a system for communication among two or more computers. They are linked together through either a physical cable,  or a wireless device. This link then allows the computers on the network to share resources such as an Internet connection, printers, files, and programs.

2. How are networks classified?

    Answer: 

    Computer networks fall into three classes regarding the size, distance  and the structure namely

1. LAN (Local Area Network)
2. MAN (Metropolitan Area Network)
3. WAN (Wide Area Network)

3. State applications of computer network.

    Answer: 

    A computer network has following applications:

1. Resource Sharing:
2. Information Sharing:
3. Person-to-person Communication:
4. Electronic Business:
5. Interactive Environment:
6. Manufacturing:
7. Marketing and Sales:
8. Banking:
9. Financial services:
10. Insurance:

4. Enlist various advantages and disadvantages of of network.

    Answer: 

    Computer Network consist of following Advantages:

1.  Speed:
2.  Cost:
3.  Security:
4.  Centralized Software Management:
5.  Resource sharing:
6.  Sharing Software:
7.  Easy communication:
8.  Flexible Access:
9.  Workgroup Computing:

    Disadvantages of Network:

1. Expensive to Install:
2. Requires Administrative Time:
3. Breakdown and Possible Loss of Resources:
4. Security Threats:
5. Bandwidth Issues:

5. What is topology?

    Answer:

    Topology is the physical layout of computers, calbes, witches, routers and others components of a network. This term can also refer to the underlying network architecture such as Ethernet or Token Ring.

    The word "topology" comes from "topos", which is a greek word for "place". When you design a network, your choice of topology will be determined by the size, architecture. cost and management of the network.

6. What are modes of communication? Explain with example.

Answer: 

    In data communication, the exchange of information takes place through transmission modes which defines the direction of the flow of information between two communication devices i.e. it tell the direction of signal flow between the two devices.

Three modes of communication are:

1. Simplex: Simplex communication runs in one direction. example:  TV and radio broadcasting or pager.
2. Half duplex: In a half-duplex transmission, the entire capacity of a channel is taken over by whichever of the two devices is transmission at the time. simplest example is a walkie-talkie. You have to press a button to talk and release the button to listen.
3. Full duplex: In full duplex, both stations can transmit and receive simultaneously. The full-duplex mode is like a two-way street with traffic flowing in both directions at the same time. example, mobile phones operate in full duplex mode when two person talk on mobile phone, both can listen and speak simultaneously.

2.  Define the following terms:

1. LAN.

    Answer: 

    LAN is a group of computers and associated peripheral devices connected by a  communications channel, capable of sharing files and other resources among several users.

2. Communication Modes.

    Answer: 

    In data communication, the exchange of information takes place through transmission modes which defines the direction of the flow of information between two communication devices i.e. it tell the direction of signal flow between the two devices.

3. Network Components.

    Answer: 

    A computer network comprises the following components:

1. Computers(at least two)
2. Cables that connect the computers to each other.
3. A network interface device on each computer ( This is called a Network Interface Card or NIC)
4. A switch (Note: hubs are no longer recommended).
5. Network operating system software.
6. Uninterruptible power supply(optional).

    all of these are called network component.

4. Wireless Network

    Answer: 

    In networking terminology, wireless is the term used to describe any computer but rather where there is no physical wired connection between sender and receiver, but rather the network is connected by radio waves and / or microwaves to maintain communications.

    The basis of wireless systems is radio waves, an implementation that takes place at the physical level of network structure.

5. Network Software

    Answer: 

    Network software interacts, increases and faciliates the function of a computer network. It has become integral part of today's computing world where shared information, effective communication and reliable productivity is needed.

3.  Answer the following questions:

1. What is Computer Network? What are its goals?

    Answer: 

    A computer network is a system for communication among two or more computers. They are linked together through either a physical cable,  or a wireless device. This link then allows the computers on the network to share resources such as an Internet connection, printers, files, and programs.

    The computer networks are playing an important role in providing services to large or small or medium organizations as well as to the individual common man. Like human being computer network provides following gorals:

1. Resource Sharing:
2. High Reliability:
3. Minimize Cost:
4. High Performance:
5. Scalability:
6. Power Communication Medium:
7. Distribution of workload:
8. Security:
9. Backups:

2. Define topology. Explain any one topology with its advantages and disadvantages.

    Answer: 

    Topology is the physical layout of computers, calbes, witches, routers and others components of a network. This term can also refer to the underlying network architecture such as Ethernet or Token Ring.

    A node is an active device connected to the network, such as as computer or a printer. It can be a piece of networking equipment such as hub, switch or a router.

Mesh Topology:

• Each device is mesh topology has a dedicated point-to-point link to every other device. Dedicated means that link carries traffic only between the two devices it connects.
• The mesh topology is generally used only in Wide Area Network(WANs) in which different networks are connected using routers. 
• fully connected mesh network has n(n - 1)/2 links for n devices. To accommodate n(n-1)/2 links, every device on the network must have n - 1 input/output (I/O) ports. Meshes use a significantly larger amount of network cabling than do the other network topologies, which makes it more expensive. The mesh topology is highly fault tolerant.
• That is, every computer has multiple possible connection paths to the other computers on the network, so a single cable break will not stop network communication between any two computers.
• A network topology in which every device is connected by a cable to every other device on the network. Multiple links to each device are used to provide network link redundancy.

Advantages:

• Each connection can carry its own data due to dedicated links.
• Eliminates traffic problem.
• Mesh topology is robust. If one link becomes unusable, it does not affect other systems.
• Privacy or Security because of dedicated line.
• Point-to-point link make fault identification easy.

Disadvantages:

• More cables are required than other topologies.
• Installation and reconfiguration is very difficult because each device must be connected to every other device.
• Expensive due to hardware requirements such as cables and input/output ports.        

3. Write a note on point-to-point and broadcast transmission.

    Answer: 

• Point-to-point network consist of many connections between individual pairs of machines of go from the source to destination.
• A packet on this type of network may have to visit one or more intermediate machine. Often multiple routes of different lengths are possible.
• So routing algorithms play an important role in point-to-point communication. Example : WAN
• It is normally a connection of routers, called as Subnet.
• If two routers, that are not connected by a direct cable and wish to communicate, they must do it via other routers. A packet is sent from one to another via. Intermediate router.
• The packet is stored until required output line is free and then forwarded.
• A subnet using this principle is called as point to point store and forward or packet switched network.
• A point-to-point network with one sender and one receiver is sometimes called Unicasting.
• Example of Point-to-Point networks are LAN(Local Area Network), MAN(Metropolitan Area Network), WAN(Wide Area Network), Internet, etc.

    Advantages:

• Simple: A point-to-point network is one of the simplest networks because it only involves two nodes.
• Cheapest and effective: This is one of the cheapest and most effective network architectures because it doesn't involve the cost of redundancies.
• Less Complex: It does not add the complexity of needing several nodes functioning to make a connection.

    Disadvantages:

• Lack of security: You have limited number of concurrent connections and anyone with access to the network can access all shared files/folder. You open yourself up to viruses/spyware/adware/rootkits and lots of other 'malware'.

• More expensive: As it requires lots of transmission lines and switching elements to connect remote hosts. It also requires a lot of bandwidth.