Expand the following:
(a) ARPANET
(b) MAC
(c) ISP
(d) URI
Answer
(a) ARPANET — Advanced Research Project Agency Network
(b) MAC — Media Access Control
(c) ISP — Internet Service Provider
(d) URI — Uniform Resource Indicator
What do you understand by the term network?
Answer
A network is an interconnected collection of autonomous computing devices that can share and exchange information and resources.
Mention any two main advantages of using a network of computing devices.
Answer
The two main advantages of using a network of computing devices are as follows:
Resource Sharing — Through a network, data, software and hardware resources can be shared irrespective of the physical location of the resources and the user.
Reliability — A file can have its copies on two or more computers of the network, so if one of them is unavailable, the other copies could be used. That makes a network more reliable.
Differentiate between LAN and WAN.
Answer
| LAN | WAN |
|---|---|
| LAN stands for Local Area Network. | WAN stands for Wide Area Network. |
| Small computer networks that are confined to a localized area up to 1km are known as Local Area Network. | The networks spread across countries or on a very big geographical area are known as Wide Area Network. |
| It usually costs less to set it up. | It costs higher to set it up. |
| It is usually a single network. | It is usually a network of many networks. |
| LANs facilitate information sharing, enhanced communication and resource sharing. | WANs facilitate information sharing and enhanced communication primarily. |
Write down the names of few commonly used networking devices.
Answer
A few commonly used networking devices are modem, hub, switch, router etc.
Two universities in different States want to transfer information. Which type of network they need to use for this?
Answer
When two universities located in different states want to transfer information between them, they would use a Wide Area Network (WAN). WANs are designed to connect devices over long distances, such as between different cities, states, or countries.
Define the term topology. What are the popular network topologies?
Answer
The arrangement of computers and other peripherals in a network is called topology. The popular network topologies are Mesh, Ring, Bus, Star and Tree.
How is tree topology different from bus topology?
Answer
Tree topology is a hierarchical structure where multiple branches can each have one or more basic topologies, such as ring, bus, or star. In this type of network, data transmitted from the source first reaches the centralized device, and from there, the data passes through every branch where each branch can have links for more nodes.
In bus topology, each communicating device connects to a transmission medium known as a bus. Data sent from a node are transmitted along the length of the bus in both directions. As a result, data can be received by any of the nodes connected to the bus.
Identify the type of topology from the following:
(a) Each node is connected with the help of a single cable.
(b) Each node is connected with central switching through independent cables.
Answer
(a) Bus Topology
(b) Star Topology
What do you mean by a modem ? Why is it used ?
Answer
A modem is a computer peripheral that allows us to connect and communicate with other computers via telephone lines. Modem stands for 'Modulator Demodulator'. The modem at the sender’s end acts as a modulator that converts the digital data into analog signals. The modem at the receiver’s end acts as a demodulator that converts the analog signals into digital data that the destination node can understand.
Explain the following devices:
(a) Switch
(b) Repeater
(c) Router
(d) Gateway
(e) NIC
Answer
(a) Switch — A switch is a networking device that connects various computing/network devices on a computer network using packet switching to receive and forward data to the destination. When data arrives, the switch extracts the destination address from the data packet and stores it in a table to determine where to send the packet. This allows the switch to send signals to only selected devices instead of broadcasting to all devices. Additionally, a switch can forward multiple packets simultaneously. One of the key features of a switch is that it does not forward noisy or corrupted signals. Instead, it drops such signals and requests the sender to resend them.
(b) Repeater — A repeater is a device that amplifies a signal being transmitted on the network. It is used in long network lines, which exceed the maximum rated distance for a single run. Over distance, the cables connecting a network lose the signal transmitted. If the signal degrades too much, it fails to reach the destination. Or if it does arrive, the degradation of the message makes it useless. Repeaters can be installed along the way to ensure that data packets reach their destination.
(c) Router — A router is a network device that forwards data from one network to another. A router works like a bridge but can handle different protocols. Based on a network road map called a routing table, routers can help ensure that packets are travelling the most efficient paths to their destinations. If a link between two routers fails, the sending router can determine an alternate route to keep traffic moving.
(d) Gateway — A gateway is a network device that connects dissimilar computer networks following different protocols. The gateways act as entry and exit point for a network as they translate communications from one network protocol to the other.
(e) NIC — The network interface card (NIC) is a device that is attached to each of the workstations and the server. It helps the workstation establish the all-important connection with the network and has a unique number identifying it, known as the node address.
Draw a network layout of star topology and bus topology connecting five computers.
Answer
Star Topology
Bus Topology
What is the significance of MAC address?
Answer
The MAC (Media Access Control) address is the physical address, which is assigned to the hardware network card (Network Interface Card), of the host computer and remains fixed. The machine on which the NIC is attached, can be physically identified on the network using its MAC address. The NIC manufacturer assigns a MAC address which is a 6 byte address (48 bits) with each byte separated by a colon. The first three bytes (24 bits) of MAC address are the manufacturer-id or the organizational unique identifier (OUI) and the last three bytes (24 bits) are the card-number.
How is IP address different from MAC address? Discuss briefly.
Answer
IP address, also known as Internet Protocol address, is a unique address that can be used to uniquely identify each node in a network. However, unlike MAC address, IP address can change if a node is removed from one network and connected to another network. A sample IP address looks like: 192.168.0.178.
The MAC (Media Access Control) address is the physical address, which is assigned to the hardware network card (Network Interface Card), of the host computer and remains fixed. The machine on which the NIC is attached, can be physically identified on the network using its MAC address. A sample MAC address looks like: FC:F8:AE:CE:7B:16.
What is DNS ? What is a DNS server ?
Answer
The character based naming system by which servers are identified is known as domain name system (DNS). DNS helps to translate domain names into IP addresses that computers can understand. It acts as a directory that matches human-readable domain names to their corresponding numerical IP addresses, allowing users to access websites without needing to remember or type in the IP addresses directly.
A DNS server is a specialised server responsible for finding the correct IP address for a given domain name. Domain Name Servers are the phone book of the Internet.
Sahil, a class X student, has just started understanding the basics of Internet and web technologies. He is a bit confused in between the terms "World Wide Web" and "Internet". Help him in understanding both the terms with the help of suitable examples of each.
Answer
The World Wide Web (WWW) is a set of protocols that allows us to access any document on the Net through a naming system based on URLs. The WWW also specifies a way, known as the Hypertext Transfer Protocol (HTTP), to request and send hypermedia documents over the Internet.
The Internet is a worldwide network of computer networks that allows all computers to exchange information with each other. They follow protocols like TCP/IP (Transmission Control Protocol/Internet Protocol) for communication.
The WWW is a small part of the Internet. We can say that the Internet is a highway that offers many services and features, and the WWW is a vehicle (like a truck) that uses this highway to transport information.