Chapter 7.1 Internet protocols and Network hardware

Question 1

What are the 5 layers of internet group protocols?

Answer 1

1) Physical Modems
2) Data Link
3) Network/ Internet
4) Transport
5) Application

Question 2

What is the Protocol & Function of Physical Modems?

Answer 2

Protocol: Modems
Function:This is the layer at which the basic
communication takes place bit by bit from device to device

Question 3

What is the Protocol & Function of Data Link?

Answer 3

Protocol: Ethernet/ WiFi
Function: This layer acts as a correspondent between
the network and physical layer. It receives requests of services from the network layer and in turn requests services from the physical layer.

Question 4

What is the Protocol & Function of Network/ Internet?

Answer 4

Protocol:Internet Protocol
Function: This layer is responsible for the transmission of data. It makes sure that the data packets reach the destination. It also performs routing i.e. deciding on the path to be taken by the packets to the destination

Question 5

What is the Protocol & Function of Transport?

Answer 5

Protocol: TCP, UDP
Function: This layer divides the data into smaller packets and writes the source and destination addresses on each packet as well as the sequence number of the packet

Question 6

What is the Protocol & Function of Application?

Answer 6

Protocol: FTP, TELNET, HTTP, SSH
Function: This layer consists of protocols which
provide services to the network layer via the transport layer.

Question 7

Explain IP

Answer 7

1 IP or Internet Protocol makes sure that the data packets reach the correct address.
2 Every device has a specific IP address consisting of 4 bytes.
3 TCP or Transmission Control Protocol ensures that the data packets are transmitted accurately.
4 It divides the data into smaller packets and attaches the following to the header details in the packet:
1. Source IP
2. Destination IP
3. Sequence number of the packet i.e. it may be the 4th packet of data

Question 8

Explain TCP

Answer 8

1 TCP makes duplicate copy of a packet in case of delay in transmission but also ensures that in the end only one copy of the data is received and is reassembled into order.
2 TCP is a connection oriented service i.e. it requires handshaking to take place before transmission of data.
3 TCP has a congestion control mechanism. This means that the speed of transmission has a maximum limit so that congestion or loss of data does not take place. Therefore it is not suited to real time applications where high bandwidths are required.

Question 9

What is HANDSHAKING?

Answer 9

This is the process which takes between two devices after a physical link is established. The devices agree on rate of data transfer, the protocol to be used, the process of interruption (i.e. devices send a signal for attention in case of non-arrival of a data packet) as well the alphabetic code to be used

Question 10

What is Parity Check?

Answer 10

• Parity Check is a check performed on transmitted data where one of the bits in a byte is checked to ensure that data transmitted is accurate:
  1 The left most bit in a byte is called the parity bit while the rest of the seven are data bits.
  2 The parity bit is set as 1 or 0 to keep the number of ones as even.
  3 Errors in transmission may disturb the bits in the data therefore the parity may be disturbed as well. A disturbed parity would thus indicate an error.
  4 However, parity check fails to detect an error of transposition i.e. when only position of a bit is changed. Moreover it may fail in case more than one bit is changed.

Question 11

What is UDP?

Answer 11

1 UDP or User Datagram Protocol, unlike TCP is a connectionless service i.e. it does not require handshaking to take place and does not have a congestion control mechanism. It is a very basic protocol.
2 Data packets are sent to the destination with its address attached to the packet. However sequence numbers are not attached to packets.
3 It is useful for real time applications such as video on demand systems.

Question 12

What is FTP?

Answer 12

1 FTP or File Transfer Protocol is an extensively used for downloading. It uses TCP/IP for transmission of data.
2 FTP allows the transfer of files over the internet between two computers.
3 It follows a client-server relationship i.e. users(client) have to log in using a username and password before being able to download files from or upload files to the server.
4 FTP is weak in terms of security and does not have any encryption. Therefore SSH or SSL protocols are used with it to provide additional security.

Question 13

What is HTTP?

Answer 13

1 HTTP is a protocol used to transfer data across internet. It is a set of rules which must be followed while transferring data such as files, image, sound, videos etc on the World Wide Web.
2 It is also based on a client-server relationship i.e. when a user opens the web browser and types in or clicks on a Uniform Resource Locater (URL), the request is sent and URL is converted into an IP address which is used to locate the server.
3 The server contains text, images etc in HTML format or PDF or in original formats.
4 HTTP daemon is the program which acts upon the requests from clients and sends the requested file to them.

Question 14

What is TELNET?

Answer 14

1 TELNET or Telecommunication Protocol is a network emulator i.e. it enables a computer to gain access to another computer and run software and execute commands on that computer.
2 The user’s computer has TELNET CLIENT SOFTWARE whereas the remote computer has TELNET SERVER SOFTWARE to make the connection possible.
3 A disadvantage of TELNET is that all the data is transferred as plain text and not in encrypted form.
4 However, it is considered helpful in detecting problems in a network. Network administrators use it to make changes to network settings and carry out diagnostic tests.

Question 15

What is SSH?

Answer 15

1 SSH or Secure Shell Protocol has the same function as the TELNET.
2 However it offers higher levels of security during the transmission of data in the sense that the data is encrypted.
3 It also uses Public Key Authentication which is a feature of encryption that allows one computer to ensure that a genuine computer is trying to communicate with it.
4 Public key is a key given by a computer to other computers to encrypt and send data to it.

Question 16

What is VOIP?

Answer 16

1 VOIP or Voice Over Internet Protocol is not a protocol but the use of internet to send voice data in form of digital data packets using internet protocols

Question 17

What is a Hub?

Answer 17

A hub is a device that can have a number of other devices or computers connected to it.

Question 18

What is a switch?

Answer 18

A network switch is a computer networking device that connects devices together on a computer network, by using packet switching to receive, process and forward data to the destination device. Unlike less advanced network hubs, a network switch forwards data only to one or multiple devices that need to receive it, rather than broadcasting the same data out of each of its ports

Question 19

What are the different types of cabling used in computer networks?

Answer 19

1 Twisted Pair
2 Coaxial cable
3 Fiber optic cable

Question 20

What is twisted pair?

Answer 20

two conducting wires twisted around each other; This reduces the magnetic interference and hence data loss in such a system

Question 21

Advantages of twisted Pair

Answer 21

1. Cheaper and far easier to splice
2. Less susceptible to electrical interference caused by nearby equipment or wires.
3. In turn are less likely to cause interference themselves.
4. Because it is electrically “cleaner”, STP wire can carry data at a faster speed.

Question 22

Disadvantages of twisted Pair

Answer 22

1. STP wire is that it is physically larger and more expensive than twisted pair
   wire.
2. STP is more difficult to connect to a terminating block.

Question 23

What is a Coaxial cable?

Answer 23

a conducting wire surrounded by a plastic non-conducting layer, which is in turn covered by a cylinder of conducting material and finally surrounded by a PVC jacket

Question 24

Advantages of Coaxial cable

Answer 24

1. Coaxial cable can support greater cable lengths between network devices than twisted pair cable.
2. Thick coaxial cable has an extra protective plastic cover that help keep moisture away.

Question 25

Disadvantages of Coaxial cable

Answer 25

1. Thick coaxial is that it does not bend easily and is difficult to install.

Question 26

What is a fiber optic cable?

Answer 26

it is optical fibers that are individual coated with a plastic resin and then sheathed in a plastic layer

Question 27

Advantages of fiber optic cable

Answer 27

1. One single mode fiber can replace a metal of time larger and heavier.
2. Multi-mode optical cable has a larger diameter and can be used to carry signal over short distance.

Question 28

Disadvantages of fiber optic cable

Answer 28

1. Fiber optic versus metal cable is that it is difficult to make connections to fiber optic cable.
2. The optical fiber must be highly polished to allow light to pass with little loss.

Question 29

What is a file servers?

Answer 29

1 File servers are normally used to store user data, for example documents, presentations, videos, spreadsheets and Database files.
2 File server allows users to save and load data using the network rather than having physical storage within the computer or without the need for any secondary storage device.

Question 30

What is a Network interface card?

Answer 30

a Network interface card (NIC) is a card that fits into a slot on the computer motherboard. It enables the computer processor to connect to other servers or other computers