A Glossary of Networking Terms - Part 3

English: wireless access point (Photo credit: Wikipedia)

In the final instalment of this trilogy of articles highlighting some of the more common computer networking terms, the three terms concerned are all common and integral to small home networks as well as enterprise levels. As such they are terms with which it is useful for many people outside of the IT industry to be familiar.

Firewall
The concept of a firewall in computing takes its name from the idea of the physical construct used to prevent fire spreading between buildings and rooms or compartments. In computing therefore, firewalls perform an analogous function preventing packets of data that may harm a computer or network from passing through - an obvious example of such packets would be viruses. In practise firewalls are therefore software applications or hardware based systems which sit on the connection points between LANs or individual devices and public WANs like the internet. They will monitor all traffic attempting to enter or leave the LAN/device and grant or deny access to it based upon rules that the user is able to predefine and control.

Gateway/Router
What is now referred to as a router was originally, and in some contexts still is, termed a gateway. It can be thought of as the hub at the heart of a network through which all communications (data packet transfers) pass. The routing element describes the process of receiving data packets from one device, determining its destination address, comparing that to a list of known devices, whether it be games consoles or dedicated hosting servers fro websites, and then forwarding the packets to that destination. Whereas the term ‘router’ has become more commonplace, the term ‘gateway’ is used more specifically to describe devices which allow communication between networks/computers/programs that use differing protocols.

Routers can take the form of physical devices or software applications and in practice many, like those used in home networks, can also provide the functions of a number of network elements such as network switches, modems (to connect to the rest of the internet), firewalls and wireless access points. They therefore also act in the more generic sense as ‘gateways’ to the local networks that sit behind them for any traffic being transferred to or from wider networks such as WANs and the internet.

Wifi/Wireless
Wifi is short for wireless fidelity and is used in general to describe technologies that deliver digital communications between devices using radio waves. Networks that utilise WiFi can interchangeably be referred to as wireless networks or wireless local area networks (WLANs). As with the wired Ethernet, the technologies are standardised by the Institute of Electrical and Electronics Engineers Standards Association (IEEE), however the actual term “Wi-Fi” is a trademark of the Wireless Alliance, who are the trade association that certify that products adhere to those standards.

WLANs are created using a Wireless Access Point (WAP) which takes wireless data and forwards it, through a wired connection, to or from a router - often WAPs are integrated into routers themselves. The areas in range of WAPs are called a wireless hotspot and are now commonplace in peoples homes as well as throughout business premises and public spaces. Often in the latter two areas, WAPs can be positioned so that hotspots overlap to provide extensive networks. The Wi-Fi standards ensure that any enabled device will be able to connect to a WAP, and, although transfer speeds across wireless networks will generally be slower than wired counterparts (and can be disrupted further by interference where competing signals use the same frequency channels) newer standards are still capable of delivering data thirsty services, such as streaming for video conferencing, without the restrictions of fixed wiring.

One of the major concerns with WLANs is security because any device within range of a WAP can see the network and pick up the signal. Consequently, there are a number of measures that are used to restrict access to private WLANs and to keep transmissions on those networks secure. Initially WEP (Wireless Equivalent Privacy) and latterly WPA (Wi-Fi Protected Access) and WPA2 have been implemented to this end to ensure that transmissions are encrypted and passwords are required in order to connect to the network. In addition, networks can be configured to only allow connections from predefined devices by using their unique MAC (Media Access Control) addresses.

A Glossary of Networking Terms - Part 2

The second instalment in this trilogy of articles explaining some of the more common terms found in networking jargon introduces two terms which may already be familiar to many computer users as technologies they make use but without necessarily a full awareness of their definitions: Ethernet and VPNs.

Ethernet
The term Ethernet is most frequently used to describe a type of network cable, common in our homes and workplaces, but actually applies to the protocol which defines the cable and its associated technologies (e.g., computer ports) that can be used to connect computer devices to each other within a network. As a result the term can even be used in some contexts to refer to the networks (predominantly LANs - Local Area Networks) themselves that they form.

The Ethernet protocol is standardised by the Institute of Electrical and Electronics Engineers Standards Association (IEEE) and is the most common such network connection used in the IT industry. The original Ethernet standard delivered a data transfer rate of 10 megabits per second and utilised copper coaxial cables (i.e., inner cable which carries signal is insulated by secondary sheet material) to do so. With the advent of successive standards such as Fast Ethernet (100 Mbit/s) the transfer rates have risen significantly up to the highest at 100 Gigabits a second. The Ethernet cables used t0o achieve these speeds have developed to include fibre optic and twisted pair (usually copper) cables alongside the original coaxial forms, with the most common and familiar cables in the home and workplace being twisted pair.

VPN
The abbreviation VPN is short for the term Virtual Private Network. This concept covers a broad array of technologies, including EVPN (Ethernet VPN), but essentially describes a secure connection between computers or LANs made across a public network such as the internet. VPNs allow communications between separate networks to be kept private and secure with no-one intercepting them and/or viewing them in transit. Whereas secure WANs may have previously relied (and in some cases still do rely) on dedicated physically distinct leased lines to ensure that the information being transferred is done so outside of the public domain, VPNs create what is called a tunnel to provide the same effect. VPN tunnels are a virtualised equivalent ‘through’ which encrypted data packets are transferred - essentially representing the idea that the data packets are cloaked to appear as though they are normal public network data transmissions without providing any visibility of the data they contain. The packets containing the core data are encrypted and encapsulated within outer packets which are further encrypted and which simply display information on which network gateway they are intended. The encrypted packets of data can only be unencrypted to view the contents when they reach the predesignated destination computer.

VPNs are a vital tool in business to allow workers to work securely off-site (as if they were in the office), to connect disparate branch offices, reduce physical business travel and to allow networks to incorporate and utilise varying types of computing device (e.g., tablet vs desktop). In turn, these opportunities all allow businesses to increase efficiency - reducing costs and boosting productivity - as well as improving flexibility and employee morale.

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.

An Introduction to Fast Ethernet

The following article aims to provide an introduction to the concept of Fast Ethernet, what it is, a summary of how it works, and who can benefit from its implementation.

The basic definition of Fast Ethernet is just that, fairly basic, in that it simply refers to Ethernet cables/connections which carry data at a rate faster than the original Ethernet speeds. This original Ethernet typically carried data at speeds of 10Mbit/s (10,000,000 bits per second) whereas services that are described as Fast Ethernet can reach speeds of 100Mbit/s. In its stricter sense the term actually applies to a number of different standards which deliver this speed although more loosely it is also used to describe the standards which have superseded it with faster transfer rates, including Gigabit Ethernet (1,000,000,000 bits a second) and in the last few years, 10Gbit/s (10,000,000,000 bits a second).

The various Fast Ethernet standards are known as 100BASE-[?] as a progression of the original Ethernet standard 10BASE-T, where [?] varies to designate the medium and method through which data is being transmitted. They are broadly split into two camps, those that use copper cables and those that run on fibre-optic cables. The copper cable variants have a designation of 100BASE-T[?] whilst the optical fibre standards include 100BASE-BX, 100BASE-FX, 100BASE-LX10 and 100BASE-SX (distinguished by the number of strands of fibre, the wavelength and the reach of the signal).

The Benefits
The obvious benefit of Fast Ethernet is the speed at which amounts of data can be transferred across the networks that use it. In a crude sense, for businesses especially, the more data that can be transferred in a given period, the quicker the business processes (that are based upon these computer functions) and the more efficient the business.

However, it’s not just a case of speeding up existing processes. Using higher bandwidth connections such as Fast Ethernet and being able therefore to transfer more data, more quickly also opens up additional avenues of technology and communication which require larger flows of data. These technologies of course have their own benefits. A good example of this is video streaming which has obvious value in terms of conveying information or as a source of entertainment, but which can also be invaluable to businesses as a communication tool using live streams to facilitate video conferencing. Furthermore, Fast Ethernet is a vital component of constructing Wide Area Networks (WANs), networks which stretch over long distances incorporating remote local area networks (LANs). These can be used by providers to offer cross-location connectivity.

Its Uses
In a personal context individuals are utilising Fast Ethernet everyday to connect up their home networks, allowing them to run centralised entertainment systems which are becoming increasingly popular. Users rely on these connections to play gaming software, stream videos and listen to music from central hubs or the internet.

In a commercial context, as mentioned above it can be a vital component of a WAN which in turn can provide businesses and organisations with secure networks across disparate geographical locations. These networks connect LANs together and therefore connect employees as if they were all on the same site. The networks allow organisations to transfer sensitive data at operational speeds and so perform demanding tasks from remote locations. They facilitate efficient, collaborative and real-time communications such as video conferencing ensuring that businesses are flexible, cohesive and responsive.

© Stuart Mitchell 2012