A Glossary of Networking Terms - Part 1

local area network (Photo credit: benschke)

Nearly every part of our lives these days will be affected, influenced and often facilitated by the use of computers and more to the point, networks of computers. Whether it be the wireless networks of PCs, games consoles and phones sharing internet connections in our homes or the vast business infrastructures that provide so many of the services we take for granted; even the internet itself. As with all areas of technology though, the world of networking is thick with jargon and so can appear very esoteric to those that don’t work within the field. This article therefore aims to summarise a few of the terms that people might stumble across in their everyday encounters with networks.

Packets
Data packets, sometimes simple referred to as packets in a computing context, are to some extent self explanatory in that they are pieces/units of digital data which are formatted into ‘packets’ in order for them to be transferred across networks. There are two elements to these packets, the information that is being transferred (sometimes called the payload) and the control data, which contains information to help it reach its destination. The control data can include details about the destination and source addresses, error checking, information about the size and type of packet (which protocols it follows) and information to help reconstruct bigger units of data where they fragmented into smaller packets. A helpful analogy is that of a letter which can contain all of the information it needs to reach its destination and be interpreted by the reader correctly, recorded before and after the content itself.

LAN vs WAN
LAN is the abbreviation of Local Area Network; WAN is the abbreviation of Wide Area Network. LANs and WANs are to some extent defined in contrast to each other.

In simple terms LANs are small networks which connect devices in one location. They are usually constructed using Ethernet cables (and their compatible technologies) and/or Wireless protocols to connect the localised devices, all behind one firewall. As a result of the proximity of devices and therefore the technologies that can be used to connect them, LANs are able to offer high speed data transfer rates between the interconnected devices. They are commonly deployed and utilised in single work locations such as offices but over the last decade or so have also become common in peoples homes to enable their computers and entertainment devices to talk to each other and share an internet connection. They are, by their nature, private networks (with communication possible between local devices behind a firewall) and usually have a single gateway to public networks such as the internet.

WANs, on the other hand, are networks which span multiple locations to interconnect individual devices or separate local networks. The term can therefore be applied to the entire network they form (including LANs) or the just the connections made between the separate localised networks. WANs can employ a variety of technologies to this effect. They can take the form of private networks where dedicated leased lines or virtual private networks are used to securely connect disparate private LANs together, or they can simply form open communication networks which the public can use to share information. In the latter sense the internet can be considered to be a variation of a WAN. Private WANs are integral fro businesses working across multiple locations to ensure that each location can interact and communicate securely and to offer the economies of scale that arise from the centralisation of infrastructure such as the use of central servers for business hosting.