ARPANET

Network Topology:

Network topology is the layout of a network. It consists of two parts; physical and logical. The physical part describes the physical layout of a network while the logical part describes how the data flows in that network. Both, physical and logical parts are also known as the physical topology and the logical topology.

Physical part (Topology) + Logical part (Topology) = Network Topology

History of Computer Networking:

A computer network is a group of computers that has the potential to transmit, receive and exchange voice, data, and video traffic. 

The network and data communication are the essential factors to rise information technology in the world as technology's advancement is on the system, including the gadgets. ARPANET began the networking long ago.

In 1957, when SPUTNIK Satellite was launched by Russia. An agency named ADVANCED RESEARCH PROJECT AGENCY (ARPA) was started by American, and its first satellite was launched within 18 months after establishment. Then they used ARPANET to share the information on another computer. America's Dr. LIED LIEDER has this all responsibility. Then, ARPANET came to India in 1969, and its name changed from Indian to NETWORK.

For the United States Department of Defense, the funding of the design of the Advanced Research Projects Agency Network (ARPANET) was began by ARPA. In 1969, the network began to develop on the basis of the developed designs in the 1960s. The below table contains a complete history of computer networking:

Year	Event
1961	In this year, Leonard Kleinrock proposed the earliest computer networks, which was the idea of ARPANET.
1965	In 1965, Donald Davies coined the term "packet" to describe how to send data between computers on a network.
1969	Although In 1966, the development of ARPANET began, officially started ARPANET in 1969. It was considered one of the first computer networks in which first two nodes, UCLA and SRI (Stanford Research Institute) were connected, and to use packet switching. To provide and define information about network protocols, procedures, and computer communications, the first RFC surfaced as a document in April 1969.
1969	On 29 August 1969, the first IMP and network switch were sent to UCLA. On ARPANET, the first data transmission was sent by using it.
1970	NCP, stands for NetWare Core Protocol, released by Steve Crocker and a team at UCLA for use with NetWare.
1971	In 1971, the first e-mail was sent to across a network to other users by Ray Tomlinson.
1973	While working at Xerox PARC, Robert Metcalfe developed the Ethernet in 1973. In the same year, ARPA deployed the first international network connection, known as SATNET. In 1973, VoIP technology and capabilities were officially introduced, which made a VoIP call. However, until 1995, the software was not available for users that could make VoIP calls.
1974	In this year, the use of first router was began, but they were not considered true IP routers.
1976	Originally called a gateway, Ginny Strazisar develop the first true IP router.
1978	In 1978, the TCP/IP protocol was developed and invented by Bob Kahn for networks; it was developed with help from Vint Cerf.
1981	In the United States, between IBM mainframe systems, BITNET was created in 1981 as a network. The U.S. National Science Foundation developed the CSNET (Computer Science Network) in the same year 1981.
1983	For using TCP/IP, ARPANET finished the transition. The first DNS implement by Jon Postel and Paul Mockapetris in 1983.
1986	This is the year in which a backbone for ARPANET, the National Science Foundation Network was came online, which finally took the place of ARPANET in 1990s. In the same year, with the original BITNET, BITNET II was introduced to deal with bandwidth issues.
1988	In 1988, the first T1 backbone was included with ARPANET. AT&T, Lucent, and NCR introduced the WaveLAN network technology in 1988. In 1988, for the first time, the explanation of network firewall technology was published. In the same year, Digital Equipment Corporation developed it. This paper had the detail about the first firewall, known as a packet filter firewall.
1990	The first network switch was developed and introduced by a U.S. network hardware company named Kalpana in 1990.
1996	In 1996, an IPv6 was introduced as an improvement over IPv4, as well as embedded encryption, improved routing.
1997	In June 1997, the 802.11 standards, containing transmission speeds up to 2 Mbps, for Wi-Fi were introduced.
1999	The 802.11a standard, containing transmission speeds up to 25 Mbps to use the 5 GHz band, was officially made in 1999. Another standard 802.11b was available to use for the public in mid-1999, which offered transmission speeds up to 11 Mbps. In September 1999, for use with 802.11b, the WEP encryption protocol was released.
2003	802.11g devices, contained transmission speeds up to 20 Mbps, were available to the public in January 2003. In the same year, for use with 802.11g, the WPA encryption protocol is released.
2004	In 2004, as a replacement for WPA, the WPA2 encryption protocol was introduced. By 2006, WPA2 certification was compulsory for all Wi-Fi devices.
2009	The 802.11n standard can operate on the 2.4 GHz and 5 GHz bandwidths and offers higher transfer speeds over 802.11a and 802.11g. Officially, it was made in 2009.
2018	In January 2018, WPA3 encryption was released by the Wi-Fi Alliance, which comprises security enhancements over WPA2.