Computer Networking Basic Questions
A computer network is a group of devices connected with each other through a transmission medium such as wires, cables etc. These devices can be computers, printers, scanners, Fax machines etc.
The purpose of having computer network is to send and receive data stored in other devices over the network. These devices are often referred as nodes. There are five basic components of a computer network:
Message: It is the data or information which needs to be transferred from one device to another device over a computer network.
Sender: Sender is the device that has the data and needs to send the data to other device connected to the network.
Receiver: A receiver is the device which is expecting the data from other device on the network.
Transmission media: In order to transfer data from one device to another device we need a transmission media such as wires, cables, radio waves etc.
Protocol: A protocol is a set of rules that are agreed by both sender and receiver, without a protocol two devices can be connected to each other but they cannot communicate. In order to establish a reliable communication or data sharing between two different devices we need set of rules that are called protocol. For example, http and https are the two protocols used by web browsers to get and post the data to internet, similarly smtp protocol is used by email services connected to the internet.
Computer network types
As networking needs evolved, so did the computer network types that serve those needs. Here are the most common and widely used computer network types:
LAN (Local Area Network): A LAN connects computers over a relatively short distance, allowing them to share data, files, and resources. For example, a LAN may connect all the computers in an office building, school, or hospital. Typically, LANs are privately owned and managed.
WLAN (Wireless Local Area Network): A WLAN is just like a LAN but connections between devices on the network are made wirelessly.
WAN (Wide Area Network): As the name implies, a WAN connects computers over a wide area, such as from region to region or even continent to continent. The internet is the largest WAN, connecting billions of computers worldwide. You will typically see collective or distributed ownership models for WAN management.
MAN (Metropolitan Area Network): MANs are typically larger than LANs but smaller than WANs. Cities and government entities typically own and manage MANs.
PAN (Personal Area Network): A PAN serves one person. For example, if you have an iPhone and a Mac, it’s very likely you’ve set up a PAN that shares and syncs content—text messages, emails, photos, and more—across both devices.
SAN (Storage Area Network): A SAN is a specialized network that provides access to block-level storage—shared network or cloud storage that, to the user, looks and works like a storage drive that’s physically attached to a computer. (For more information on how a SAN works with block storage, see Block Storage: A Complete Guide.)
CAN (Campus Area Network): A CAN is also known as a corporate area network. A CAN is larger than a LAN but smaller than a WAN. CANs serve sites such as colleges, universities, and business campuses.
VPN (Virtual Private Network): A VPN is a secure, point-to-point connection between two network end points. A VPN establishes an encrypted channel that keeps a user’s identity and access credentials, as well as any data transferred, inaccessible to hackers.
Features of a Computer Network
A computer network has following features:
Performance: Performance of a computer network is measured in terms of response time. The response time of sending and receiving data from one node (computer in a computer network are often referred as node) to another should be minimal.
Data Sharing: One of the reason why we use a computer network is to share the data between different systems connected with each other through a transmission media.
Backup: A computer network must have a central server that keeps the backup of all the data that is to be shared over a network so that in case of a failure it should be able to recover the data faster.
Software and hardware compatibility: A computer network must not limit all the computers in a computer network to use same software and hardware, instead it should allow the better compatibility between the different software and hardware configuration.
Reliability: There should not be any failure in the network or if it occurs the recovery from a failure should be fast.
Security: A computer network should be secure so that the data transmitting over a network should be safe from unauthorised access. Also, the sent data should be received as it is at the receiving node, which means there should not be any loss of data during transmission.
Scalability: A computer network should be scalable which means it should always allow to add new computers (or nodes) to the already existing computer network. For example, a company runs 100 computers over a computer network for their 100 employees, lets say they hire another 100 employees and want to add new 100 computers to the already existing LAN then in that case the local area computer network should allow this.
Basic components of a computer network
Computer Network Components
Server: Servers are computers that runs operating system and hold data that can be shared over a computer network.
Client: A client is a computer that is connected to other computers in the network and can receive data sent by other computers.
Transmission Media: All computers in a computer network are connected with each other through a transmission media such as wires, optical fibre cables, coaxial cables etc.
Network Interface card: Each system or computer in a computer network must have a card called network interface card (NIC). The main purpose of NIC is to format the data, send the data and receive the data at the receiving node.
Hub: Hub acts as a device that connects all the computer in a network to each other. Any request that comes from a client computer first received by Hub and then hub transmit this request over a network so that the correct server receives and respond to it.
Switch: Switch is similar to hub however instead of broadcasting a incoming data request it uses the physical device address in the incoming request to transfer the request to correct server computer.
Router: Router joins multiple computer networks to each other. For example lets say a company runs 100 computers over a local area network(LAN) and another company runs another LAN of 150 computers. These both LANs can be connected with each other through a internet connection which is provided by the router.
LAN cable: A wire that is used to connect more than one computers or other devices such as printers and scanner to each other.