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computer network

By Kinza Yasar

What is a computer network?

A computer network is a group of interconnected nodes or computing devices that exchange data and resources with each other. A network connection between these devices can be established using cable or wireless media. Once a connection is established, communication protocols -- such as TCP/IP, Simple Mail Transfer Protocol and Hypertext Transfer Protocol -- are used to exchange data between the networked devices.

The first example of a computer network was the Advanced Research Projects Agency Network. This packet-switched network was created in the late 1960s by ARPA, a U.S. Department of Defense agency.

A computer network can be as small as two laptops connected through an Ethernet cable or as complex as the internet, which is a global system of computer networks.

How does a computer network work?

Devices attached to a computer network use IP addresses that are resolved into hostnames through a domain name system server to communicate with each other over the internet and on other computer networks. A variety of protocols and algorithms are also used to specify the transmission of data among endpoints.

Network systems must follow certain standards or guidelines to operate. Standards are a set of data communication rules required for the exchange of information between devices and are developed by various standards organizations, including IEEE, the International Organization for Standardization and the American National Standards Institute. For example, the Ethernet standard establishes a common communication language for wired or physical networks, and the 802.11 standard specifies connectivity for wireless local area networks (WLANs).

A computer network must be physically and logically designed in such a way that makes it possible for the underlying network elements to communicate with each other. This layout of a computer network is known as the computer network architecture.

The following are the two most common computer network architectures:

  1. Client-server. This model consists of many clients -- or nodes -- where at least one network node acts as the central server. The clients in this model don't share resources, but request the central server, as all the resources are installed on it.
  2. Peer-to-peer (P2P). Each connected device on this network behaves as the client, as well as the server, and enjoys similar privileges. The resources of each peer are shared among the entire network, including memory, processing power and printing. Many companies use the P2P architecture to host memory-intensive applications, such as three-dimensional rendering, across multiple network devices.

A well-defined computer network also takes network capacity into account. A network's capacity is how much traffic the network can support at any given time, while still meeting service-level agreements. It's measured in terms of bandwidth, which is quantified by the theoretical maximum number of bits per second that can pass through a network device.

Core components of a computer network

The following building blocks -- network devices, links and communication protocols -- make computer network operations possible:

TCP/IP is a conceptual model that suggests the following four functional layers for these communication links:

  1. Network access layer. This layer defines how the data is physically transferred through the network, as well as how hardware devices send bits through a network medium, such as coaxial, optical, fiber or twisted-pair cables.
  2. Internet layer. This is the layer where routing takes place. It packages data into packets and enables them to be sent and received over the network. The internet layer includes IP, Address Resolution Protocol and Internet Control Message Protocol.
  3. Transport layer. This layer ensures the stable, sequenced and error-free delivery of data packets. It achieves this by swapping acknowledgment of data reception and retransmitting lost or dropped packets. Typical protocols used at the transport layer include TCP and User Datagram Protocol.
  4. Application layer. Security protocols, such as Transport Layer Security, operate at this layer and play an integral part in ensuring network security. This is the abstraction layer that communicates directly with applications and defines how high-level apps should access the network to start a data transfer. For example, the application layer is used to define where, when and how much data should be sent at a specific rate.

The modern internet architecture is mostly built on the TCP/IP model, which is the simplified version of the more conceptual Open Systems Interconnection model.

Advantages of using a computer network

Computer networks are ideal for the quick exchange of information and the efficient use of resources.

The following are benefits of using a computer network:

Types of computer networks

There are several types of computer networks. Which network an organization uses depends on factors such as the number of devices, types of operating systems, transmission medium used, network topology, the distance between each device and their geographic scale.

Some examples of computer networks are the following:

Networks can be divided into subnetworks, also called subnets.

What are the different types of network topologies?

A network topology is the physical and logical arrangement of a network. All topologies come with different pros and cons. Organizations should consider the scope of a network -- including its size, scaling needs and business goals -- before selecting a particular topology.

Network topologies include the following types:

Computer networks come in all shapes and sizes. Explore the seven common types of networks, along with their pros and cons.

28 Mar 2023

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