Archive for the ‘Networks’ Category

How Do Wireless Networks Work?

Friday, August 7th, 2009

Wireless networks work using radio waves instead of wires to transmit data between computers. That’s the simple version. If you’re curious to know what’s going on in more detail, then it’s all explained in this article.

Ones and Zeros.

I’m sure you know that computers transmit data digitally, using binary: ones and zeros. This is a way of communicating that translates very well to radio waves, since the computer can transmit ones and zeros as different kinds of beep. These beeps are so fast that they’re outside a human’s hearing range — radio waves that you can’t hear are, in fact, all around you all the time. That doesn’t stop a computer from using them, though.

Morse Code.

The way it works is a lot like Morse code. You probably already know that Morse code is a way of representing the alphabet so that it can be transmitted over radio using a dot (short beep) and a dash (long dash). It was used manually for years, and became a great way of getting information from one place to another with the invention of the telegraph. More importantly for this example, though, it is a binary system, just like a computer’s ones and zeros.

You might think of wireless networking, then, as being like Morse code for computers. You plug a combined radio receiver and transmitter in, and the computer is able to send out its equivalent of dots and dashes (bits, in computer-speak) to get your data from one place to another.

All About Frequencies.

You might wonder, though, how the computer could possibly transmit enough bits to send and receive data at the speed it does. After all, there must be a limit on how much can be sent in a second before it just becomes useless nonsense, right? Well, yes, but the key to wireless networking is that it gets around this problem.

First of all, wireless transmissions are sent at very high frequencies, meaning that more data can be sent per second. Most wireless connections use a frequency of 2.4 gigahertz (2.4 billion cycles per second) — a similar frequency to mobile phones and microwave ovens. As you might know, though, a frequency this high means that the wavelength must be very short, which is why wireless networking only works over a limited area.

In addition, wireless networks make use of a technique known as ‘frequency hopping’. They use dozens of frequencies in the range they are given, and constantly switch between them. This makes wireless networks more immune to interference from other radio signals than they would be if they only transmitted on one frequency.

Access Points.

The final step is when it comes to all the computers on a network sharing Internet access. This is done using a special piece of wireless equipment called an access point. Access points are more expensive than wireless cards for one computer, as they contain radios that are capable of talking to around 100 computers at the same time, and sharing out access to the Internet between them. Dedicated access points are only really essential for larger networks, though — if you only have a few computers, it is possible to use one of them as the access point, or you could just get a wireless router.

They Understand Each Other.

That’s all well and good, then, but how does wireless equipment made by entirely different companies manage to work together when this is all so complicated? Well, the answer is that there are standards that all wireless devices follow. These standards are technically called the 802.11 standards, and are set by the IEEE (Institute of Electrical and Electronics Engineers). It is thanks to people sticking to their standards that wireless networking is so easy and cheap to use today.

You Don’t Need to Worry.

If all this talk of frequencies has you a little worried, you don’t need to be — wireless networking hardware and software handles all of this automatically, without you needing to do a thing. Don’t think that you’re going to have to tell one wireless device what frequency another is using, because it’s just not going to happen, alright? Wireless networking, for all its complicated workings, is really far more simple to use than you’d ever expect.

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Computer Networking Fundamentals

Friday, August 7th, 2009

A computer network is a collection of two or more computers with communication between them through a medium. The communication medium can be through radio waves, wires, infrared, optical fibers etc.

Computer network is an integral part of our daily lives, with the most important reason being that of communication. The use of computer networking is to share resources like fax machines, printers, modems, files etc., and its other uses are database server, computer server, email, chat, internet etc. The computer to which the resources are attached is called the server and the other computers that access the resource are called clients. In peer-to-peer computer networks there are no servers.

The sharing of fax machines, printers, and modems amongst many computers and users reduce the operational cost. A database on a computer network is a very important application as it stores and runs many important data and jobs. Emails and chats can be used for instantaneous communication and sending of files on a computer network.

The computer networks are classified, depending upon the size, as Local Area Networks (LAN), Wide Area Networks (WAN), Metropolitan Area Networks (MAN) and Personal Area Networks (PAN). The topology (topology is the way the computer networks and network resources are connected) of the networking can be classified as Bus Network, Ring Network and Star Network.

The networking hardware basically consists of wiring, network cards and a hub. Computer network cards are required so that one computer can understand what the other computer is “talking”. Network cards have a unique MAC address to identify computers on a computer network. Hubs connect all the computers in the network. Hubs can also be used to connect to other hubs to increase the size of the computer network. Two computers can be connected using Ethernet cards or phone lines or power lines for communication, with hardware kits available at roughly a cost of $100.

As the number of computers in an office or a home increases, so do the number of cables, so wireless networking is a viable solution. In wireless networking radio transreceivers or infrared signals are used to communicate between computers and devices. Examples of wireless networking include Wi-fi and Bluetooth technology, though there may be security issues involved in wireless networking. However there definitely is a stronger preference towards wireless networking nowadays among consumers.

Computer networks have added a new dimension to the 21st century. Today the cyber world is much faster and wider than the real world. This has all been made possible due to computer networks. Computer networks have revolutionized business, communication, travel, research, defense, society and almost all human endeavors. The evolution of computer networks has helped the technological revolution take a big leap forward.

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Computer Network Management

Friday, August 7th, 2009

Today it is almost inconceivable for a business not to have computers, whether it is a construction company or a high technology firm. When a business has more than one computer, they are almost always connected together in a local area network. These networks may be more or less advanced and therefore more or less costly.

Companies invest so much (in terms of both money and time) in a local area networks because there are many advantages that a local area network brings to a business and how it is administered.

Some businesses use a local area network in such a way they are highly dependent on it always working. If the company’s network fails, then you may see all the employees chatting away in the corridors because they can’t do their work. This means big losses for the company and causes stresses on the employees. All companies must consider their local area networks a vital asset and downtime must be avoided. This imposes huge demands on the network staff to keep such networks running almost 100% of the time.

The advantages of Computer Network Management

One of the main advantages of installing and maintaining LANs is the opportunity they create for better communication and cooperation between employees and customers.

Security considerations: Local Area Network security can be both a help and hindrance. Comprehensive security is beneficial because it provides a central and safe strategy for data access and disaster recovery. All information is protected by the design and implementation of the network security solution. On the other hand, interconnecting computers in local area networks creates a security risk, since doing so makes it technically possible for intruders to access many machines on the network at once.

Cost considerations: Installing a local area network is a relatively expensive project. Servers, cabling, switches, routers and software can all be expensive and should never be purchased without expert advice. Keeping the network operating and secure also requires a lot of resources and can be costly.

Surprisingly, a local area network can bring a number of cost savings. Sharing resources avoids the need to purchase equipment for each individual. Even more important is the security that a local area network can provide. Data loss could cost a business a great deal of money and in some cases, cause the business to shutdown altogether. Computer Network Management should require a consistent routine for data backups with regular checkups of data quality – a practice that will save a company huge sums in the event of a mishap.

Computer Network Management: preliminary analysis phases

The first phase of computer network management is to determine the source of the problem (a preliminary study that looks into several options of differing scope may be useful here) and defining it in a specification of requirements. Examples of what should be evaluated are different network operating systems, mail systems, and other applications. The choice of hardware components should also be evaluated. This phase is generally aimed at establishing what the system should do, not how it should do it.

Computer Network Management: design phase

The purpose of design phase is to determine how the requirements of the specification are to be met. The current approach to large, complex projects is to break them down into smaller, more manageable subprojects.

Computer Network Management: implementation phase

This phase involves the physical installation of the local area network. Cables are run, software is installed, and computers and other hardware are put in place.

Computer Network Management: integration and system testing phase

In this phase, commissioning of the network begins, and routines are adapted to users and the operating personnel. The system must be tested, both to ensure that the network meets the requirements set out in the specification and that it is stable enough to perform the central function it has in the organization.

Computer Network Management: operation and maintenance

Local area networks have complex operating routines. This is because there may be serious consequences when faults occur or unauthorized persons gain access to the system. Many companies have employees devoted solely to take care of running and maintaining computer networks. These system administrators may deal with network issues such as performance, reliability and security of both hardware and software.

Computer Network Management: tools

Although an organization may have computer administrators on site, they must also monitor the network more than eight hours a day. In fact, some of the worst trouble that arises with networks can happen during the night hours when nobody is using the network. With the right computer network management tools, your organization can receive the security of knowing that problems will be foreseen, prevented, and taken care of – and that your network administrator can be notified at a moment’s notice, should anything go exceptionally wrong.

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