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Initially, the scope of ARPANET was restricted to military and research. Subsequently, its use extended to education
by supporting various educational institutes. In the 1970s, other networks such as SatNet (Satellite Network), Packet
Radio, and Ethernet LAN came into being. Different networks deployed different technologies. So, a unifying mechanism
was required to enable communication between the networks with heterogeneous technologies. Towards this end,
Cerf and Kahn developed TCP/IP (Transmission Control Protocol/Internet Protocol) in 1970. TCP/IP became the de facto
standard for communication during the early eighties. It facilitated interconnectivity amongst heterogeneous networks.
In late 1984, National Science Foundation (NSF) created NSFNET — a network with six supercomputers that aimed to
promote advanced research and education. Several regional networks of universities could access these supercomputers
via a computer network. Subsequently, in the 1990s, several other countries and regions developed their networks for
scientific and commercial purposes. When ARPANET and NSFNET were interconnected, the network growth increased
tremendously. This vast network formed the Internet (network of networks), and its growth connected the whole world.
In the mid-1990s, the number of hosts connected through the Internet grew exponentially. Several organisations in
government and private sectors (collectively called Internet Service Providers (ISPs)) joined hands to provide Internet
connectivity. The Internet made it possible to exchange information and communicate with remote hosts. The Internet
provides several services such as
• Email: Sending and receiving electronic messages.
• File Transfer: Files can be copied/transferred from one system to another.
• Newsgroup: A newsgroup is a discussion forum where users of related interest can post information and reply to
others’ posts.
• Remote login: Remote login enables users on one system to log into a remote system and use hardware and
software available at the remote computer.
• Chat: Chat provides real-time communication between two or more users. It allows the connected users to exchange
messages in a chat window. Examples of chat applications include WhatsApp, Facebook messenger, and Telegram.
• Video Conferencing: Video Conferencing allows multiple users to exchange video and voice messages in real-time.
Examples: Video calls using applications like Facebook and WhatsApp, or more sophisticated tools like Google
Meet, Zoom Meetings, Cisco Webex.
• Cloud Computing: Cloud Computing enables storage and computing services over the Internet. For example,
Google Cloud Platform (GCP), Amazon Web Services (AWS), and Microsoft Azure enable collaborative computing
environments.
• Interspace: Interspace is a client/server software tool that allows users to connect online in dynamic 3D worlds
using real-time audio, video, and text chat.
Interspace is a client/server software program that allows multiple users to communicate.
1. Rimit and Azaad are connected with each other through video and voice in real time. Which internet
service are they using?
2. Abha has created a document in Google Drive and shared it with her friends. Is she using a Cloud
Computing service?
6.3 Network Topologies
We already know that a network connects computers and devices (collectively called nodes). The arrangement of
nodes in a network is called topology. It describes the placement of various network devices and physical connections
between them. We will discuss various topologies of networks in this section.
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