Easy IT elements – Networks explained

When you think about the abstract term networks you may imagine social networks, i.e. how people connect and interrelate with each, or fixed configurations like rail and road networks.

In IT and business system(s) we are interested in both, the connectivity of physical components as well as the more intangible flows of information, control and influence.

(Ed. The IT Elementary School glossary definition of ‘systems’ does not distinguish between Business and IT – to be honest there isn’t a real difference for the purposes of this article.)

I won’t talk a great deal about social networks or social media, as that is a topic for another time, so let’s start with a traditional computer network.

Take one computer

Computer Networks per the simple example below should be fairly self-explanatory; without knowing the specifics of the technology involved you can see a [mostly] fixed configuration of physical devices that you might use, for example, to design your IT infrastructure.and subsequent maintenance and support  of the same.

The internet ‘cloud’ and lightning bolt needs a bit more explaining, but first a bit of history.

Computers started as big static specialist machines with connected peripheral hardware for communicating with people and other related technology, such as terminals (recognisable as predecessors of desktop computers), data entry devices, printers, external memory etc. These were essentially proto-networks that required some basic elements to function;

• Communication channels between the devices, initially hard-wired, but we will move onto wireless later.
• A configuration or ‘topography’. For now imagine the computer or mainframe as the hub of a wheel with devices connected on spokes radiating outwards, called a ‘star’, i.e. all communication, data and controls are routed through the centre.
• A common language and messaging protocol; essentially the rules that define how the connected devices communicate.
• Access rights to define who is allowed to connect to the computer/network and with what permissions.

Net-working

As more organisations got access to smaller and cheaper computers and a diversity of software applications there was a need to bring IT out of the laboratory and into the office, classroom and factory, but also to keep shared facilities and communication channels available to many. Local Area Networks or ‘LANs’ provided some different networking options and configurations, such as a bus, a ring, a tree or a mesh.

More complex networks still use the same basic elements but need a guide or a map to show what is connected to what, rather that following the cables along the computer room floor! They also start to demonstrate an increasing physical separation between the end-users and the hardware, mostly brokered by layers of dedicated systems software. The black-art of networks became – and still is – both an enabler of increased access and efficiency, and a virtual world of technology and middleware between the consumer (the ‘client’) and the service provider or resources that they want to use. There may not be any moving parts, but like a complicated machine, more complexity also means more things that can go wrong!

The next challenge was to move from a single physical location to connect remote facilities or multiple local networks together to create a Wide Area Network (you guessed it, a WAN) either within an organisation or point-to-point (‘peer-to-peer’) with other trading partners. WANs can use the regular public telephone network, dedicated fixed landlines, or wireless technologies. As you can imagine the potential for both accidental and deliberate loss, misuse or corruption of data becomes bigger where access is available to more people or can be intercepted by unauthorised third parties. The creation of protective ‘fire-walls’ and the broader subjects of encryption and cyber-security are beyond the scope of this IT element.

Casting a wider net

The next evolution – in fact in parallel to the above – was the internet, or inter-network. The early experiments connected American universities in a very similar way to the WAN model above, but the key difference was the dynamic flexible topography and the way that messages could be routed along different paths to a different endpoint based on a directory or registry of devices (using ‘IP’ Internet Protocol addresses). These new protocols and messaging standards opened the way for a massive network with no single owner or any meaningful static representation, hence the ‘cloud’ metaphor where all the nodes, channels, devices and users live (they don’t really). The lightning symbol is another shorthand for any non-fixed connectivity to remote devices, services or things.

Everything is connected

Let me return to the broader subject of networks, what they represent, and how.

Other examples of networks include:

–        Wiring diagrams, engineering or other design blueprints.

–        People, roles or functions in an organisation.

–        IT software systems/applications, for example to illustrate how different components, modules or sub-systems fit together.

–        The logical structure of Data or the physical storage of the same.

–        A  Project showing tasks to be completed and dependencies.

–        All the pages available on a website, called a site map.

–        Road or rail networks.

To unlock the full power of a picture or graphical representation of a network requires a common understanding of the notation between the creators, readers and users. As long as there is a ‘key’ to explain what the symbols mean, basically anything with nodes or junction points and connections or links in-between, can be represented or modelled as a network.

This list provides some interesting insights:

* Networks are fixed representations of ‘what’ the things are, rather than ‘how’ they are used. Other modelling and diagramming techniques provide different perspectives on data and information movement (‘flow’), sequence, state changes, and other dynamic behaviour.

* They can be real – represent the real world – or some future design or even a logical or virtual construct.

* They can be specific instances of things or generic ‘classes’ of things. For example, each railway station or person in an organisation chart is unique, but a container/symbol representing a data class or role may not be.

* They normally contain a set of similar objects such as people, webpages or tasks. It is possible to show a mixed collection of different things, although this would be a meta-model, not a meta-network.

I hope this module has helped to explain some of the basic terminology about networks, and show why they are important for making sense of an increasingly complex world, IT/technology or otherwise.

Just imagine trying to navigate the London Underground without a map!

(c) 2015 Antony Lawrence CBA Ltd.