Linking up the nodes means making some sort of a temporary or permanent connection between them. In the last decade or so, wireless connections have become one of the most popular ways of doing this, especially in homes. In offices, wired connections are still more commonplace—not least because they are generally faster and more secure and because many newer offices have network cabling already in place.
From radio to Wi-Fi
The adapter has a network card built into it. Apart from computers, peripherals, and the connections between them, what else do you need? Each node on a network needs a special circuit known as a network card or, more formally, a network interface card or NIC to tell it how to interact with the network. Most new computers have network cards built in as standard. If you have an older computer or laptop, you may have to fit a separate plug-in circuit board or, in a laptop, add a PCMCIA card to make your machine talk to a network.
A MAC code is a bit like a phone number: any machine on the network can communicate with another one by sending a message quoting its MAC code. In a similar way, MAC codes can be used to control which machines on a network can access files and other shared resources. For example, I've set up my wireless link to the Internet so that only two MAC codes can ever gain access to it restricting access to the network cards built into my two computers.
Next Generation Networking: Wi‑Fi 6
That helps to stop other people in nearby buildings or in the street hacking into my connection or using it by mistake. The bigger you make a network, the more extra parts you need to add to make it function efficiently. Signals can travel only so far down cables or over wireless links so, if you want to make a big network, you have to add in devices called repeaters —effectively signal boosters.
You might also need bridges , switches , and routers —devices that help to link together networks or the parts of networks, which are known as segments , regulate the traffic between them, and forward traffic from one part of a network to another part. Photo: Computer architecture: We can think of computers in layers, from the hardware and the BIOS at the moment to the operating system and applications at the top.
We can think of computer networks in a similar way. Computers are general-purpose machines that mean different things to different people. Some of us just want to do basic tasks like word processing or chatting to friends on Facebook and we couldn't care less how that happens under the covers—or even that we're using a computer to do it if we're using a smartphone, we probably don't even think what we're doing is "computing"—or that installing a new app is effectively computer programming.
At the opposite end of the spectrum, some of us like modifying our computers to run faster, fitting quicker processors or more memory, or whatever it might be; for geeks, poking around inside computers is an end in itself. Somewhere in between these extremes, there are moderately tech-savvy people who use computers to do everyday jobs with a reasonabe understanding of how their machines work.
Because computers mean different things to different people, it can help us to understand them by thinking of a stack of layers: hardware at the bottom, the operating system somewhere on top of that, then applications running at the highest level. You can "engage" with a computer at any of these levels without necessarily thinking about any of the other layers.
Learn about the glue that holds our networks together in this LAN primer.
Nevertheless, each layer is made possible by things happening at lower levels, whether you're aware of that or not. Things that happen at the higher levels could be carried out in many different ways at the lower levels; for example, you can use a web browser like Firefox an application on many different operating systems, and you can run various operating systems on a particular laptop, even though the hardware doesn't change at all. Computer networks are similar: we all have different ideas about them and care more or less about what they're doing and why. If you work in a small office with your computer hooked up to other people's machines and shared printers, probably all you care about is that you can send emails to your colleagues and print out your stuff; you're not bothered how that actually happens.
But if you're charged with setting up the network in the first place, you have to consider things like how it's physically linked together, what sort of cables you're using and how long they can be, what the MAC addresses are, and all kinds of other nitty gritty. Again, just like with computers, we can think about a network in terms of its different layers—and there are two popular ways of doing that. Perhaps the best-known way is with what's called the OSI Open Systems Interconnect model , based on an internationally agreed set of standards devised by a committee of computer experts and first published in It describes a computer network as a stack of seven layers.
The lower layers are closest to the computer hardware; the higher levels are closer to human users; and each layer makes possible things that happen at the higher layers:. OSI was conceived as a way of making all kinds of different computers and networks talk to one another, which was a major problem back in the s, s, and s, when virtually all computing hardware was proprietary and one manufacturer's equipment seldom worked with anyone else's.
If you've never heard of the OSI model, that's quite probably because a different way of hooking up the world's computers triumphed over it, delivering the amazing computer network you're using right now: the Internet. In this example, suppose you're emailing someone over the Internet.
Guide Wireless Home Networking Simplified (Networking Technology)
Your two devices are, in effect, connected by one long "cable" running between their network cards. That's what the green Network Access layer at the bottom represents. Your email is transmitted as packets orange squares using the Internet Protocol IP , illustrated by the orange Internet layer. At the top, in the Application layer, you sit at your computer using an email program an application that uses all the layers below.
As we saw above, higher levels of the basic computing models are independent of the lower levels: you can run your Firefox browser on different Windows operating systems or Linux , for example. The same applies to networking models. And you can hook your computer to the net using WiFi or wired broadband or dialup over a telephone line different forms of network access.
In other words, the higher levels of the model are doing the same jobs even though the lower levels are working differently. Like highways or railroad lines that connect towns and cities, computer networks are often very elaborate, well-planned things. In the days when computers were big static boxes that never shifted from data centers and desktops, computer networks also tended to be fairly static things; often they didn't change much from one week, month, or year to the next.
The Internet, for example, is based on a set of well-defined connections called the Internet backbone including vast submarine cables that obviously have to stay in place for years. That's computer networking at one extreme. Increasingly, though, we're shifting to mobile devices that need to improvise networks as they move around the world. Wi-Fi wireless Ethernet is one example of how smartphones, tablets, and other mobile computers can join and leave fixed networks based around "hotspots," or access points in a very ad-hoc way. Bluetooth is even more improvized: nearby devices detect one another, connect together when you give them permission , and form a generally short-lived computer network—before going their separate ways.
Ad-hoc technologies like these are still based on classic computer networking concepts, but they also involve a range of new problems. How do mobile devices discover one another? How does one device such as a Wi-Fi router know when another abruptly joins or leaves the network? How can it maintain the performance of the network when lots of people try to join at the same time?
What if all the network devices are using slightly different versions of Wi-Fi or Bluetooth; will they still be able to connect? If communication is entirely wireless, how can it be properly secured? We discuss these sorts of issues in more detail in our main articles about Wi-Fi and Bluetooth.
Not so long ago, computers were all made by different companies, worked in different ways, and couldn't communicate with one another. May 9, May 8, February 15, January 21, January 8, December 4, November 30, November 7, October 24, Share on Facebook. Share on Twitter. Recent Posts. Cloud Services Will Continue to Rise. The transceiver implements spread spectrum technology and the controller to run the protocol.
The CEBus standard is an open standard that provides separate physical layer specifications for communication on power lines and other media. Data packets are transmitted by the transceiver at about 10 Kilobits per second Kbps , using spread spectrum technology. The CEBus protocol uses a peer-to-peer communications model so that any node on the network has access to the media at any time. Basically, this Media Access Control MAC protocol requires a network node to wait until the line is clear, which means that no other packet is being transmitted before it can send a packet.
In the upper layer, CEBus includes a common application language CAL that allows devices to exchange commands and status requests. It defines a common command syntax and vocabulary to do this. CAL defines various electronic device functional sub-units called contexts. And each context is further divided into objects, which represent various control functions of the context.
- 100% Cloud-Managed IT.
- How to Build and Maintain the Best Home Network;
- How do computer networks work? - Explain that Stuff?
- The Customer Rules: The 39 essential rules for delivering sensational service.
- Mer fra Jim Doherty; Neil Anderson (Brigham Young University).
- Wireless Home Networking Simplified (e-bok) | ARK Bokhandel;
Objects are furtherly defined by a set of instance variablesthat specify the operation of the function of the object. Intellon offers products ranging from chip sets to board solutions, depending on the level of integration the manufacturer wants to perform on their own. But the cost issues have made Intellon chips less affordable and thus they are not widely used as X10 devices.
Echelon offers a 10 Kbps power line chip based on spread spectrum technology. Echelon also offers a sophisticated proprietary MAC protocol embedded in their Neuron chip, providing the peer-to-peer networking layer. It provides a complete platform on which to build control systems.
Neuron Chip in LONWorks family includes an implementation of the LonTalk protocol along with other built-in features to provide a complete system-on-a-chip solution for control devices. Inside this chip, LonTalk protocol support many communication media including, twisted pair, power line, fiber optics, coaxial cable, radio frequency, and infrared. FSK modulation sends digital signals over the power line by using two or more separate frequencies that are in a fairly narrow band. It also provides reasonable data rates of 1 Mbps and above.
However, power-line networking is still in its childhood. Data integrity across power-line networks is still a big issue, particularly in homes with older wiring. Data security between houses and apartments is not sufficiently protected in the current standards. Future efforts are needed to make powerline networking a capable competitor for phoneline networking.
But most of them are targeted at low-speed automation controls. Currently, in Radio Frequency bands, there has been a lot of research work in telecommunication and networking industry. The IEEE It operates at MHz and 2. And it can sustain a 1Mbps to 2Mbps data rate. Once equipped, they are suitable for a home office network. However, the current cost per port of installing an Two primary groups are working to develop affordable wireless home-networking standards: Bluetooth and the HomeRF Working Group.
Figure 3 shows the basic topology of an The AP is analogous to a basestation used in cellular phone networks.
Home Networking Simplified
Region Allocated Spectrum US 2. Operating principles of DSSS radios are described in the following paragraphs. For more information of IEEE This consortium is working toward a low-cost, global standard for wireless communication of data and voice. The Bluetooth technology is based on a short-range radio link built into small application-specific integrated circuits ASICs.
It can support both stationary and mobile communications and use frequency hopping up to 1, hops per second to reduce noise impact. Bluetooth supports data transmissions between devices of up to Kbps and up to three voice channels. Operating in the unlicensed and globally available industrial, scientific, and medical ISM band at 2. Bluetooth technology can enable a user to replace the various cables between devices with a universal short-range radio link. And they could interoperate with similarly equipped devices such as printers, fax machines, desktop computers and peripherals, and a host of other digital devices.
Futhermore, Bluetooth technology can provide a connection between the ad hoc network and existing data networks. As claimed, Bluetooth technology is designed for wireless personal area networks WPANs , which are networks of personal electronic devices in close proximity to each other. Bluetooth technology is expected to become a major player in the wireless data communications market because of simplicity and its support from large companies.
And Bluetooth members are encouraging vendors to incorporate the technology into their products by waiving intellectual property royalty fees. It is a subset of the International Telecommunication Union ITU and specially works on the development of a standard for inexpensive RF voice and data communication.
Furthermore, it includes four personal communication services PCS -quality voice channels for cordless telephones.
Related Wireless Home Networking Simplified (Networking Technology)
Copyright 2019 - All Right Reserved