Computer Networks

Networking is the exchange of information and ideas among people with a common profession or special interest, usually in an informal social setting. Networking often begins with a single point of common ground.

Computer networking enables devices and endpoints to be connected to each other on a local area network (LAN) or to a larger network, such as the internet or a private wide area network (WAN). This is an essential function for service providers, businesses and consumers worldwide to share resources, use or offer services, and communicate. Networking facilitates everything from telephone calls to text messaging to streaming video to the internet of things (IoT).

Network packet

Most modern computer networks use protocols based on packet-mode transmission. A network packet is a formatted unit of data carried by a packet-switched network. The physical link technologies of packet network typically limit the size of packets to a certain maximum transmission unit (MTU). A longer message is fragmented before it is transferred and once the packets arrive, they are reassembled to construct the original message.

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 (see ‘Nodes’ below). A VPN establishes an encrypted channel that keeps a user’s identity and access credentials, as well as any data transferred, inaccessible to hackers.

Components of networking

Computer networking requires the use of physical network infrastructure — including switchesrouters and wireless access points — and the underlying firmware that operates such equipment. Other components include the software necessary to monitor, manage and secure the network.

Additionally, networks rely on the use of standard protocols to uniformly perform discrete functions or communicate different types of data, regardless of the underlying hardware.

Computer networks and the internet

The internet is actually a network of networks that connects billions of digital devices worldwide. Standard protocols allow communication between these devices. Those protocols include hypertext transfer protocol (the ‘http’ in front of all website addresses). Internet protocol (or IP addresses) are the unique identifying numbers required of every device that accesses the internet. IP addresses are comparable to your mailing address, providing unique location information so that information can be delivered correctly.

Internet Service Providers (ISPs) and Network Service Providers (NSPs) provide the infrastructure that allows the transmission of packets of data or information over the internet. Every bit of information sent over the internet doesn’t go to every device connected to the internet. It’s the combination of protocols and infrastructure that tells information exactly where to go.

How do they work?

Computer networks connect nodes like computers, routers, and switches using cables, fiber optics, or wireless signals. These connections allow devices in a network to communicate and share information and resources.

Networks follow protocols, which define how communications are sent and received. These protocols allow devices to communicate. Each device on a network uses an Internet Protocol or IP address, a string of numbers that uniquely identifies a device and allows other devices to recognize it. 

Routers are virtual or physical devices that facilitate communications between different networks. Routers analyze information to determine the best way for data to reach its ultimate destination. Switches connect devices and manage node-to-node communication inside a network, ensuring that bundles of information traveling across the network reach their ultimate destination.

Security

Computer network security protects the integrity of information contained by a network and controls who access that information. Network security policies balance the need to provide service to users with the need to control access to information.

There are many entry points to a network. These entry points include the hardware and software that comprise the network itself as well as the devices used to access the network, like computers, smartphones, and tablets. Because of these entry points, network security requires using several defense methods. Defenses may include firewalls—devices that monitor network traffic and prevent access to parts of the network based on security rules.

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