Computer Network

A computer network is a group of computer systems and other computing hardware devices that are linked together through communication channels to facilitate communication and resource-sharing among a wide range of users. Networks are commonly categorized based on their characteristics. A computer network is a system in which multiple computers are connected to each other to share information and resources.

Characteristics of a Computer Network

• Share resources from one computer to another.

• Create files and store them in one computer, access those files from the other computer(s) connected over the network.

• Connect a printer, scanner, or a fax machine to one computer within the network and let other computers of the network use the machines available over the network.

• Network Cables

• Distributors

• Routers

• Internal Network Cards

• External Network Cards

T568B / T568A Pinouts

Pin	T568B	T568A
1	white with orange stripe	white with a green stripe
2	orange	green
3	white with a green stripe	white with orange stripe
4	blue	blue
5	white with blue stripe	white with blue stripe
6	green	orange
7	white with brown stripe	white with brown stripe
8	brown	brown

Following is the list of hardware's required to set up a computer network.

Network Cables:

Network cables are used to connect computers. The most commonly used cable is Category 5 cable RJ-45...

Two standard RJ45 pinouts define the arrangement of the individual eight wires needed when attaching connectors to a cable: the T568A and T568B standards. Both follow a convention of coating individual wires in one of five colors — brown, green, orange, blue, or white — with certain stripe and solid combinations.

Following either the T568A or T568B convention is essential when you build your own cables to ensure electrical compatibility with other equipment. If you don't build your own cables, you only need to verify the correct standard for use with your equipment.

For historical reasons, T568B is the more popular standard, although some homes use the T568A version. The table below summarizes this color coding of the wires in the connectors.

Distributors:

• Router:
• Network Card
• Internal Network Cards
• External Network Cards
• Wired and wireless technologies
• LANs, WANs, MANs, and SANs

Types of computer network topologies

• Full mesh networks, in which all nodes are connected to each other and can exchange data.

• Partial mesh networks, in which some of the nodes are connected to each other in a full mesh scheme, but others are only connected to one or two other nodes in the network.

• Point to point networks, which is a connection between only two endpoints.

• Network fabric, in which endpoints transfer data to each other through interconnecting switches and can connect to any other by taking a path through a criss-cross pattern of connections.

• A tree network, which is a combination of two or more star networks connected together.

• A star network, in which the nodes are connected to a common central computer.

• A Bus, a circuit arrangement where all network devices are attached directly to a transmission line directly, and while all signals pass through all devices, each device has a unique identity and recognizes signals intended for it.

Several other kinds of connectors closely resemble RJ45s, and they can be easily confused with one another. The RJ11 connectors used with telephone cables, for example, use six position connectors rather than eight position connectors, making them slightly narrower than RJ45 connectors.

Other than that, they look very much the same.

A computer can be connected to another one via a serial port but if we need to connect many computers to produce a network, this serial connection will not work.

The solution is to use a central body to which other computers, printers, scanners, etc. can be connected and then this body will manage or distribute network traffic.

Features 24 autosensing, autonegotiating 10-/100-/1000-Mbps ports;

 four are dual-media ports, which may be used as Gigabit Ethernet UTP or SFP portsAccepts 1250-Mbps SFPs.Rackmount brackets are included.

The LGB524A is a gigabit Ethernet switch with 20 10/100/1000 Mbps RJ45 ports and 4 dual media gigabit ports for RJ45 or SFP connections. Typical applications include LAN connectivity for remote workgroups or buildings that require fiber links for longer reach. The switch delivers line rate, nonblocking throughput. Ports are auto-negotiating half/full duplex and include LED indicators to view port status. This unmanaged switch is plug and play and does not require any configuration.

A router is a type of device which acts as the central point among computers and other devices that are a part of the network. It is equipped with holes called ports. Computers and other devices are connected to a router using network cables. Nowadays router comes in wireless modes using which computers can be connected without any physical cable.

A wireless router is a device that performs the functions of a router and also includes the functions of a wireless access point. It is used to provide access to the Internet or a private computer network.

A network card is a necessary component of a computer without which a computer cannot be connected over a network. It is also known as the network adapter or Network Interface Card (NIC). Most branded computers have network card pre-installed. Network cards are of two types: Internal and External Network Cards.

The motherboard has a slot for internal network card where it is to be inserted. Internal network cards are of two types in which the first type uses Peripheral Component Interconnect (PCI) connection, while the second type uses Industry Standard Architecture (ISA). Network cables are required to provide network access.

External network cards are of two types: Wireless and USB based. Wireless network card needs to be inserted into the motherboard, however, no network cable is required to connect to the network.

Network devices including switches and routers use a variety of protocols and algorithms to exchange information and to transport data to its intended endpoint. Every endpoint (sometimes called a host) in a network has a unique identifier, often an IP address or a Media Access Control address, that is used to indicate the source or destination of the transmission. Endpoints can include servers, personal computers, phones and many types of network hardware.

Networks may use a mix of wired and wireless technologies. Network devices communicate through a wired or wireless transmission medium. In wired networks, this may consist of optical fiber, coaxial cable or copper wires in the form of a twisted pair. Wireless network pathways include computer networks that use wireless data connections for connecting endpoints. These endpoints include broadcast radio, cellular radio, microwave, and satellite.

Networks can be private or public. Private networks require the user to obtain permission to gain access. Typically, this is granted either manually by a network administrator or obtained directly by the user via a password or with other credentials. Public networks like the internet do not restrict access.

Networks may also be categorized by the scope of their domains. Local area networks (LANs) interconnect endpoints in a single domain. Wide area networks interconnect multiple LANs, and metropolitan area networks interconnect computer resources in a geographic area. Storage area networks interconnect storage devices and resources. Networks may also be divided into subnetworks, also called subnets.

Network protocols and standards specify exactly how data should be transmitted and received. Modern, packet switched networks use protocols -- TCP/IP being the most widespread -- to establish a standard means of communication. The Ethernet standard establishes a common language for wired networks to communicate; the 802.11 standard does the same for wireless LANs.

A network's capacity -- that is, how much traffic it can transmit at any one time -- is measured in terms of bandwidth. Bandwidth is quantified by the theoretical maximum number of bits per second that can pass through a network device. Throughput is a measure of the actual speed of a successful transmission after accounting for factors like latency, processing power and protocol overhead.

Network topologies represent the physical or logical structure of a network, with common topologies that include the following major types: