Introduction to Networks

This post aims to simplify the concept of computer networks and networking in general.

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What networking is

Networking is the interconnection of computing devices typically at least two or more together.

A network can be simple – involving at least two computing devices, or complex –involving several millions of devices example smart watches, mobile phones, personal computers, servers etc.

What is the essence of networking?

The whole essence of networking is communication which involves resource and information sharing. This purpose hasn’t changed for generations and it actually won’t.

What can networking do for us?

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Computer Networks gives us that flexibility to share resources, information etc.

Files can be shared with ease, information can be disseminated a lot faster, resources can be shared e.g scanners, printers etc.

Home automation, remote access and monitoring is possible as a result of networking. In the corporate world, applications are shared.

In all of this, cost is significantly reduced for instance the cost of having a licensed application running on all workstations in an organization and installing printers per workstation is high compared to hosting the app on a server where every workstation can access and connecting a printer to the network.
But how is it possible to interconnect devices together for one purpose ?

The Open Systems Interconnection (OSI) model gives a clear picture on computer networking. It explains the essential components and the activities that take place in computer networks.

Open Systems Interconnection Model

The OSI model is a layered design and is widely seen as a standard architecture for networks.

Physical Layer

The physical layer is the physical representation of a network including cable types, radio links etc. On receiving data, signals are being converted to binary (0s and 1s) and are sent to layer 2. The physical layer specifies the data flows across a network and the rate of flow (transmission rate).

Data Link Layer

The data link layer is divided into two sub layers: Logical Link control layer and Media Access Control (MAC) layer. Data is converted to frames, errors are handled and frames are synchronized at this layer.

Network Layer

The network layer specifies a way to uniquely identify each device on a network by way of logical addressing (Internet Protocol (IP) addressing) and determines a suitable route from the sender to the receiver widely known as Routing.

Transport Layer

Transport layer is responsible for complete delivery of a message being sent and provides acknowledgement upon successful transmission of data; in any occurrence of an error, it re-transmits the data. It takes services from the network layer and provides same to the application layer.

Session Layer

This layer is responsible for authenticating a connection, establishing a connection, maintaining it and terminating a session.

Presentation Layer

This layer handles encryption and decryption of data. It also compresses and translates data.

Application Layer

This layer directly interacts with the end user providing services like file transfer, web surfing, mailing etc. many protocols including Simple Network Management Protocol (SNMP), Simple Mail Transfer Protocol (SMTP), Telnet, Trivial File Transfer Protocol (TFTP) etc.

Components of Computer Networks

A typical network consists of the following:

End devices

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Could either be a client or a server. It is used to access and share a resource.

When used to share a resource, it is called a server and when used to access a resource, it is called a client. Examples of end devices include workstations, personal computers, smart phones, smart watches, servers, network printers etc.

Transmission Media

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This implies the means by which communication is established. Depending on the type of network, two types of media exists:

Wired: This involves interconnecting devices via cables such as coaxial cables, Ethernet cables, fiber optic cables.

Wireless: This involves data transmission using the radio frequency spectrum.

Network Devices

These are devices that are used to build a network. They include: routers, switches, access points, network interface adapters, gateways, firewalls etc.

Types of Networks

There are different types of networks based on the geographic al area the purpose of the network

They are:

Local Area Network

Metropolitan Area Network

Personal Area Network

Wide Area Network

…more to come on networks; please stay connected