Networking Fundamentals

COURTESY :- vrindawan.in

Wikipedia

A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are made up of telecommunication network technologies, based on physically wired, optical, and wireless radio-frequency methods that may be arranged in a variety of network topological.

The nodes of a computer network can include personal computers, servers, networking hardware, or other specialised or general-purpose hosts. They are identified by network addresses, and may have host names. Hostnames serve as memorable labels for the nodes, rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol.

Computer networks may be classified by many criteria, including the transmission medium used to carry signals, bandwidth, communications protocols to organize network traffic, the network size, the topology, traffic control mechanism, and organizational intent.

Computer networks support many applications and services, such as access to the World Wide Web, digital video, digital audio, shared use of application and storage servers, printers, and fax machines, and use of email and instant messaging applications.

Computer networking may be considered a branch of computer science, computer engineering, and telecommunications, since it relies on the theoretical and practical application of the related disciplines. Computer networking was influenced by a wide array of technology developments and historical milestones.

A computer network or data network is a telecommunications network that allows computers to exchange data. Networked computing devices pass data to each other in the form of packets across connections established using either cable or wireless media.
A network packet is a formatted unit of data sent through a network to the destination. Once packets arrive, they are reassembled into their original message.
Wired media includes coaxial cable, twisted-pair cable, and optical fiber.
Wireless local area network connections use spread spectrum technology based on a common flavor of open-standards wireless radio-wave technology defined as IEEE 802.11 and known as Wi-Fi.
A network interface controller (NIC) is hardware that provides a computer with the ability to access the transmission media, and has the ability to process low-level network information.

In Ethernet networks, each NIC has a unique 48-bit Media Access Control (MAC) address.
An Internet Protocol address (IP address) is a numerical label assigned to each device participating in a network that uses the Internet Protocol for communication. An IP address serves two principal functions: host identification and network addressing.
IP addresses are 32-bit (IPv4) or 128-bit (IPv6) numbers usually written and displayed in human-readable notations, such as 198.51.100.1 (IPv4), and 2001:db8:0:1234:0:567:8:1 (IPv6).
IP addresses are assigned to a host either anew at the time of booting, or permanently by fixed configuration of its hardware or software. Persistent configuration is also known as using a static IP address. In contrast, in situations when the computer’s IP address is assigned newly each time, this is known as using a dynamic IP address.
Static IP addresses are manually assigned to a computer by an administrator.
Dynamic IP addresses are assigned either by the computer interface or host software itself through automatic configuration, or assigned by a server using Dynamic Host Configuration Protocol (DHCP).

A switch is a device that connects and filters multiple network segments or devices, by forwarding data only to one or multiple devices that need to receive the data based on destination MAC address.
A router is a device that forwards data packets between different computer networks based on network address (IP address).
A modem is a device used to connect network nodes via wire not originally designed for digital network traffic, by modulating the digital signal to produce an analog signal for transmission.
A firewall is a device used to control network security and access rules by rejecting access requests from unrecognized sources while allowing actions from recognized ones.
An access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, or related standards.

In the late 1950s, a network of computers was built for the U.S. military Semi-Automatic Ground Environment (SAGE) radar system using the Bell 101 modem. It was the first commercial modem for computers, released by AT&T Corporation in 1958. The modem allowed digital data to be transmitted over regular unconditioned telephone lines at a speed of 110 bits per second (bit/s).
In 1959, Christopher Strachey filed a patent application for time-sharing and John McCarthy initiated the first project to implement time-sharing of user programs at MIT. Stratchey passed the concept on to J. C. R. Licklider at the inaugural UNESCO Information Processing Conference in Paris that year. McCarthy was instrumental in the creation of three of the earliest time-sharing systems (Compatible Time-Sharing System in 1961, BBN Time-Sharing System in 1962, and Dartmouth Time Sharing System in 1963).
In 1959, Anatoly Kitov proposed to the Central Committee of the Communist Party of the Soviet Union a detailed plan for the re-organisation of the control of the Soviet armed forces and of the Soviet economy on the basis of a network of computing centres. Kitov’s proposal was rejected, as later was the 1962 OGAS economy management network project.
In 1960, the commercial airline reservation system semi-automatic business research environment (SABRE) went online with two connected mainframes.
In 1963, J. C. R. Licklider sent a memorandum to office colleagues discussing the concept of the “Intergalactic Computer Network”, a computer network intended to allow general communications among computer users.
Throughout the 1960s, Paul Baran and Donald Davies independently developed the concept of packet switching to transfer information between computers over a network. Davies pioneered the implementation of the concept. The NPL network, a local area network at the National Physical Laboratory (United Kingdom) used a line speed of 768 kbit/s and later high-speed T1 links (1.544 Mbit/s line rate).
In 1965, Western Electric introduced the first widely used telephone switch that implemented computer control in the switching fabric.
In 1969, the first four nodes of the ARPANET were connected using 50 kbit/s circuits between the University of California at Los Angeles, the Stanford Research Institute, the University of California at Santa Barbara, and the University of Utah. In the early 1970s, Leonard Kleinrock carried out mathematical work to model the performance of packet-switched networks, which underpinned the development of the ARPANET. His theoretical work on hierarchical routing in the late 1970s with student Farouk Kamoun remains critical to the operation of the Internet today.
In 1972, commercial services were first deployed on public data networks in Europe, which began using X.25 in the late 1970s and spread across the globe. The underlying infrastructure was used for expanding TCP/IP networks in the 1980s.
In 1973, the French CYCLADES network was the first to make the hosts responsible for the reliable delivery of data, rather than this being a centralized service of the network itself.
In 1973, Robert Metcalfe wrote a formal memo at Xerox PARC describing Ethernet, a networking system that was based on the Aloha network, developed in the 1960s by Norman Abramson and colleagues at the University of Hawaii. In July 1976, Robert Metcalfe and David Boggs published their paper “Ethernet: Distributed Packet Switching for Local Computer Networks” and collaborated on several patents received in 1977 and 1978.
In 1974, Vint Cerf, Yogen Dalal, and Carl Sunshine published the Transmission Control Protocol (TCP) specification, RFC 675, coining the term Internet as a shorthand for inter networking.
In 1976, John Murphy of Data point Corporation created ARCNET, a token-passing network first used to share storage devices.
In 1977, the first long-distance fiber network was deployed by GTE in Long Beach, California.
In 1977, Xerox Network Systems (XNS) was developed by Robert Metcalfe and Yogen Dalai at Xerox.
In 1979, Robert Metcalfe pursued making Ethernet an open standard.
In 1980, Ethernet was upgraded from the original 2.94 Mbit/s protocol to the 10 Mbit/s protocol, which was developed by Ron Crane, Bob Garner, Roy Ogus, and Yogen Dalal.
In 1995, the transmission speed capacity for Ethernet increased from 10 Mbit/s to 100 Mbit/s. By 1998, Ethernet supported transmission speeds of 1 Gbit/s. Subsequently, higher speeds of up to 400 Gbit/s were added (as of 2018). The scaling of Ethernet has been a contributing factor to its continued use.

A computer network extends interpersonal communications by electronic means with various technologies, such as email, instant messaging, online chat, voice and video telephone calls, and video conferencing. A network allows sharing of network and computing resources. Users may access and use resources provided by devices on the network, such as printing a document on a shared network printer or use of a shared storage device. A network allows sharing of files, data, and other types of information giving authorized users the ability to access information stored on other computers on the network. Distributed computing uses computing resources across a network to accomplish tasks.

Networking Fundamentals by Richard M. Roberts

A computer network or data network is a telecommunications network that allows computers to exchange data. Networked computing devices pass data to each other in the form of packets across connections established using either cable or wireless media.
A network packet is a formatted unit of data sent through a network to the destination. Once packets arrive, they are reassembled into their original message.
Wired media includes coaxial cable, twisted-pair cable, and optical fiber.
Wireless local area network connections use spread spectrum technology based on a common flavor of open-standards wireless radio-wave technology defined as IEEE 802.11 and known as Wi-Fi.
A network interface controller (NIC) is hardware that provides a computer with the ability to access the transmission media, and has the ability to process low-level network information.

In Ethernet networks, each NIC has a unique 48-bit Media Access Control (MAC) address.
An Internet Protocol address (IP address) is a numerical label assigned to each device participating in a network that uses the Internet Protocol for communication. An IP address serves two principal functions: host identification and network addressing.
IP addresses are 32-bit (IPv4) or 128-bit (IPv6) numbers usually written and displayed in human-readable notations, such as 198.51.100.1 (IPv4), and 2001:db8:0:1234:0:567:8:1 (IPv6).
IP addresses are assigned to a host either anew at the time of booting, or permanently by fixed configuration of its hardware or software. Persistent configuration is also known as using a static IP address. In contrast, in situations when the computer’s IP address is assigned newly each time, this is known as using a dynamic IP address.
Static IP addresses are manually assigned to a computer by an administrator.
Dynamic IP addresses are assigned either by the computer interface or host software itself through automatic configuration, or assigned by a server using Dynamic Host Configuration Protocol (DHCP).

A switch is a device that connects and filters multiple network segments or devices, by forwarding data only to one or multiple devices that need to receive the data based on destination MAC address.
A router is a device that forwards data packets between different computer networks based on network address (IP address).
A modem is a device used to connect network nodes via wire not originally designed for digital network traffic, by modulating the digital signal to produce an analog signal for transmission.
A firewall is a device used to control network security and access rules by rejecting access requests from unrecognized sources while allowing actions from recognized ones.
An access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, or related standards.
Objectives and skills for the network fundamentals portion of IC³ certification include:
Objectives
- Identify network fundamentals and the benefits and risks of network computing
  - Internet Connection: Speed, wired, wireless, security, network types and features, capabilities, publicly switched networks, DNS, addressing, LAN vs. WAN, VPN
  - Network troubleshooting: Solve simple scenarios, identify common problems, define IP addressing