Networking Primer – Part 3: Application, Presentation and Session Layers

Previous: Networking Primer – Part 2: Defining Networking with OSI and TCP/IP Suite

I’ve decided to group the top three layers together into one post. This is because these are more related to the data to be transmitted across the network, rather than the underlying transport mechanisms themselves. These three layers deal with the semantics of the communication, such as who the data will be sent to, the format of the data and the etiquette to be adhered too between the communicating nodes.

Lego Pirate Ship

The Pirate Ship: As with most technical concepts, analogies can help us understand the underpinning processes which are happening as part of the communication. For this series, I’m going to use the following analogy: I work in an office in Manchester and I’d like to send a pirate ship made of Lego to a friend, Rich, who works in an office in […]

Networking Primer – Part 2: Defining Networking with OSI and TCP/IP Suite

Previous: Networking Primer – Part 1: Introduction

What is a network?

This may sound like a very basic question, but I’ll assume the lowest common denominator here and define this briefly.

A network is set of two or more computing entities (nodes) that are configured to communicate with each other by passing information across an interconnecting media.

Ok, now we got that out of the way, we can talk about how exactly those nodes communicate with each other in a way that makes sense and achieves our objective of passing information between them.

A Little History

It is easy to imagine how the first baby steps of networking which occurred in the mid-20th century. As with all technology we start with the simplest goal and see how we can use what tools we available to use to achieve that goal. I’m not going to go into sending signals down telegraph wires, etc. but […]

Networking Primer – Part 1: Introduction

The world of networking has been fairly static for many years now. It’s been historically characterised by static infrastructures that require infrequent changes. These configuration changes were performed via command line interfaces by network engineers, usually sitting with a laptop and a cable plugged directly into a piece of networking hardware. Activities were manual, repeated for every individual device and extremely error prone due to the non-human readable nature of network configuration information.

The workloads running in the modern datacenter have most definitely changed in recent years. It has become apparent that the capabilities of current networking devices and operational approaches simply cannot keep up with the pace of change. In the modern datacenter, the rapid and overwhelming success of server virtualisation has fundamentally changed the way applications consume resources and the network has become somewhat of a bottleneck in providing agile, reliable and cost effective means of […]

Software Defined X – Automation: Job Stealer or Job Enabler?

I’ve had many conversations in recent weeks about the commoditization of the data center with many being concerned about the effect of the diminishing need for specialist hardware and greater automation through software. More specifically, how that might affect the job prospects of administrators and other technical roles in the modern IT environment.

We are in an era of rapid evolutionary change and this can be unsettling for many as change often is. There seems to be a wide variety of reactions to these changes. At one end there is the complete denial and a desire to retain the status quo, with an expectation that these industry changes may never occur. In the middle, we have those that tip their hat in recognition of the general direction of the trends, but expect things to happen more gradually and then there are those that embrace it with an expectation of gaining some […]