(i) Network is a broad term similar to system. Network is a communication system which supports many users. In relation with the computers, we can say that a "computer network" is a system which allows communication among computers connected in the network.
(ii) A computer network is the interconnection of two or more computers. It is done to enable the computers to communicate and share the available resources.

(i) Spam can be defined as irrelevant or unsolicited messages sent over the internet. These are usually sent to a large number of users for advertising, phishing, spreading malware, etc.
(ii) Spamming is the process of sending digital junk mail: unsolicited communication sent in bulk over the internet or through any electronic messaging system.

(i) Ecommerce or electronic commerce refers to transactions conducted via the internet. Ever time individual and companies are buying or selling products and services online they are engaging in ecommerce.
(ii) Ecommerce is a popular term for electronic commerce or even internet commerce.
(iii) Examples of ecommerce: Amazon, flipkart, eBay, Olx, Quikr,

Subscriber Channel:
1. At the point when you purchase in to a channel, any new accounts it disseminates will show up in your Subscriptions feed.When it purchase in to a channel we'll normally send you admonitions about the highlights from that channel.
2. You can pick to get a notification each time the channel circulates content by changing your notification settings. Note that accepting you pull out and, re-purchase in to a channel, your admonition settings will be reset.
Straight-Tip:
1. A fiber-optic link connector that utilizes a blade attachment and attachment. It was the primary accepted standard connector for most business wiring.
2. For bi-directional transmission, two fiber links and two ST connectors are utilized.
MT-RJ connector:
1. MT-RJ is a fiber-optic Cable Connector that is well known for little structure factor gadgets because of its little size.
2. Lodging two strands and mating along with finding pins on the attachment, the MT-RJ comes from the MT connector, which can contain up to 12 filaments.
3. The MT-RJ is one of the recently arising little structure factor connectors that are getting more normal in the systems administration industry.

1. A hub is the most basic networking device that connects multiple computers or other network device together.
2. It joins together the workstations, printers, and servers on a network to communicate with each other.
3. Each hub has a number of ports that connect it to the other devices via a network cable.
4. A hub connects all the devices on its port together.
5. When data arrives at one port, it is sent to the other ports so that all the devices can see all the information, commonly known as packets.
6. There is no intelligence in hub about what devices are connected to hub. When one device sends packet to the hub, it just broadcasts the packet on all ports.

Web Browser:
Internet Browser is an Application program that shows a World wide web report. It ordinarily utilizes the web access to get to the archive.
Web Server:
Web worker is a program or the PC that offer types of assistance to different projects called customer.
Web Page:
A page (or site page) is a hypertext report given by a site and showed to a client in an internet browser. A site ordinarily comprises of many pages connected together in a rational style. The name "page" is an allegory of paper pages bound together into a book.
At the point when the web worker gets the solicitation, it look through its stores to track down the fitting page. On the off chance that the web worker can find the page, it distributes to the HTML contained inside, delivers these bundles to the program (utilizing HTTP), and communicate them back across the organization.

Different types of wireless technologies are:
1. Bluetooth:
(i) It is named after a Danish king named Harald Bluetooth.
(ii) Bluetooth is used to connect different electronic devices wirelessly to a system for transferring and sharing data.
(iii) Cell phones are connected to hands-free earpieces, wireless keyboard, mice and mike to laptops with the help of Bluetooth as it transmits information from one device to other device.
2. Infrared:
(i) Infrared technology is a type of wireless communication technology to transfer data between two infrared enabled devices through infrared radiation.
(ii) This technology plays a very important role in wireless data communication
(iii) Infrared is used in devices such as the mouse, wireless keyboard and printers.
3. Wi-Fi:
(i) Wi-Fi is a low-cost wireless communication technology.
(ii) A Wi-Fi setup consists of a wireless router which serves a communication hub, linking portable device with an internet connection.
(iii) This network facilitates connection of many devices depending on the router configuration.
4. Radio link:
(i) A radio link is a wireless connection(also called wireless Point-to-Point connection) between two nodes, or radio units, in a data network.
(ii) Each radio unit consists of a transceiver(a device that can both send and receive communication) and a highly directive antenna.
(iii) The antenna only emits or receives power in the direction it is pointing.
5. Microwave Link:
(i) Microwave is a line-of-sight wireless communication technology that uses high frequency beams of radio waves to provide high speed wireless connections that can send and receive voice, video and data information.
(ii) One of the reasons microwave links are so adaptable is that they are broadband.
(iii) They require no equipment or facilities between the two terminal points, so installing a microwave link is often faster and less costly than a cable connection.
5. Microwave Link:
(i) Microwave is a line-of-sight wireless communication technology that uses high frequency beams of radio waves to provide high speed wireless connections that can send and receive voice, video and data information.
(ii) One of the reasons microwave links are so adaptable is that they are broadband.
(iii) They require no equipment or facilities between the two terminal points, so installing a microwave link is often faster and less costly than a cable connection.
6. Satellite Link:
(i) Satellite communication is one of the wireless technologies, used to transfer the signals from the transmitter to a receiver with the help of satellites.
(ii) It is widely spread all over the world allowing users to stay connected virtually anywhere on the Earth.
(iii) The Satellites used in this mode of communication, communicate directly with the orbiting satellites via radio signals.

Different types of computer networks are:
1. LAN(Local Area Network):
(i) The local area network is a network which is designed to operate over a small physical area such as an office, factory or a group of buildings. LAN are widely used in variety of applications.
(ii) In LAN all the machines are connected to a single cable. Different topologies such as Bus, Ring, Star, Tree, etc. are used for LANs.
(iii) The size of LAN is usually small. The various devices in LAN are connected to central devices called Hub or Switch using a cable.
(iv) A LAN is usually a privately owned and links the devices in a single office, building or campus of up to few kilometres in size.
(v) The data rate for LAN can now range from 4 to 16 Mbps.
2. MAN(Metropolitan Area Network):
(i) A MAN is basically a bigger version of LAN. It is designed to extend over the entire city. MANs extend beyond 100 KM.
(ii) The MAN can be in the form of a single network such as a cable network or it can be a combination of multiple LANs.
(iii) A MAN may be wholly owned and operated by a private company or it may be a service provided by a public company, such as local telephone company(telco).
3. WAN(Wide area network):
(i) When a network spans a large distance or when the computers to be connected to each other are at wide separated locations a local area network cannot be used. For such situation, a Wide area Network(WAN) must be installed.
(ii) The communication between different users of WAN is established using leased telephone lines or satellite links and similar channels.
(iii) A WAN provides a long-distance transmission of data, voice image and video information over large geographical areas that may comprise a country, a continent or even the whole world.
(iv) WANs may use public, leased or private communication devices, and can spread over a wide geographical area. WAN that is wholly owned and used by a single company is often called as enterprise network.
(v) In most WANs the network contains a large number of cables or telephone lines each one connecting a pair of routers.
4. PAN (Personal area network):
(i) A personal area network, or PAN, is a computer network that enables communication between computer devices.
(ii) PANs can be wired, such as USB or FireWire, or they can be wireless, such as infrared, ZigBee, Bluetooth and ultra-wide band (UWB).
(iii) The range of a PAN typically is a few meters. Examples of wireless PAN (WPAN) are devices include cell phone, headsets, wireless keyboards, wireless mice, printers, bar code scanners and game consoles.
(iv) Hence computer network are classified into four types based on the size, distance and the structure namely: LAN (Local Area Network), MAN (Metropolitan Area Network), WAN (Wide Area Network) and PAN (Personal Area Network).