Saturday, August 22, 2009

Terminals

What is driving forward wireless data? Well, there are several important factors. One of the most important is the advent of smaller and more powerful portable computers. These machines mean that people can be much more mobile than in the past. A computer on its own is a powerful tool, but a computer attached to a network is even more powerful. So wireless users wish to exploit the full power of their laptops by connecting them to networks.

Another force pushing the uptake of wireless communications is the Personal Digital Assistant or PDA such as the Apple Newton, US Robotics PalmPilot or the Psion. These small, handheld devices were initially little more than electronic diaries, but with the development of more powerful processors they have evolved into sophisticated machines in their own right, capable of reading and sending e-mail, faxes and surfing the web. These devices are becoming more and more popular due to their low price and high functionality. Connection to the internet or the intranet improves their usefulness.

The improvements made in radio modem technology are also important in the market place. When Mobitex first came into commercial use in 1986 the radio equipment required was huge - it took up a significant part of a car's boot. It was mobile, but only if you had a car, there was no way in the world that you could use it in hand held terminals. Mobitex modems are now available on PC Cards, which are the size of a credit card and about a centimetre thick - a big improvement on the old technology. So now it is feasible to use one of these modems in a portable PC or PDA.

Of course, the decrease in cost of all these items and the wireless data services means that they are becoming available to a greater portion of the market which in turn means a larger subscriber base.

What's going to happen in the future is very hard to say. Bernt Ericsson, Ericsson's research manager, has talked about wireless multi-media application that would allow two-way,wireless video conferencing. Telia, Sweden's state owned PSTN operator have a vision of wireless multi-media communications at the cost of today's telephone calls. In a similar vein, Ericsson are currently involved in Sweden's largest ever research project to deliver a wireless multi-media network with a bit rate of 10 Mbps by the year 2005.

internet and intranet


We use the internet as an access tool for different services, for example e-mail, web browsing and newsgroups. But how do we access the internet itself? Well, this is done in many different ways. You can use a normal dial-up modem, a satellite access system, an IR LAN, ISDN or the cable TV network. There are lots of different ways to connect yourself to the internet (or the corporate intranet), and there are pros and cons associated with each.


However, the single, most flexible method is, by a long way, the use of a Public Land Mobile Network, or PLMN. Only a PLMN can give you the ability to access the internet from wherever you are, and only a PLMN can give you this access while you are mobile. This is why PLMNs are becoming so important. When you're at home, there are several different access technologies to choose from. Similarly, when you're at work, there are several possible methods of connecting to the 'net. But when you're out driving your car, the only way of accessing on-line information is via a PLMN.

IP Every Where

With this picture we can see the strength of IP - it's flexibility. If we imagine the hourglass as representative of three layers of the protocol stack, we can see why IP is so popular.

IP is flexible enough to run on top of most protocols, so you can run IP on an Ethernet network, you can run IP on a X.25 network, you can run IP on a FDDI network or an ATM network. IP doesn't really care about the underlying network technology - it will run on all of them.

Similarly, IP will support lots of different services. So you can run your e-mail software on top of IP, you can surf the web, you can read Usenet and so on. IP is flexible enough to offer all these services.

This is the key to IP's success - it's flexibility. It will happily run on top lots of different networks and will happily support lots of different services. This is the beauty of IP.

Tag

Assignment Lanka Tag Cloud
Computer Networks The History of Local Area Networks, LAN, The Topologies of a Networks, LANs describe different types of transmission Medias, Local Area Networks Access Methods, Carrier Sense Multiple Access with Collision Detect, Development of LAN Technologies. LAN -Token Ring, LAN Ethernet Digital, LAN - Ethernet Sun microsystems, LAN - Ethernet Mixed Environment, LAN - Token Ring was introduced by IBM LAN - IBM implementation of Token Ring, Token Ring Novell, LAN Token Ring - in a mixed environment, LAN - Fiber Distributed Data Interface, LAN - ATM, LAN Components, LAN Switching Methods, Virtual Local Area Network, Port based VLAN, Mac based VLAN, Protocol based VLAN, User Base VLAN, PC networks Components, PC networks Shared resources, PC Network operating systems, PC networks Novell Netware, PC networks Windows NT, PC networks IBM LAN Server Computer Programming Languages HTML Language, The Generations of Programming Languages, Different types of High Level Languages, Different types of High Level Languages Disadvantages
Computer Networks - IBM LAN Server, Windows NT Networks, Novell Netware, Network operating systems, Networks Shared, Networks Components, User Base, Protocol based, Mac based, Port based, VLAN, LAN Switching, LAN Components, ATM, Fiber Data, Token Ring, Token Ring Novell, IBM implementation, Ethernet, Sun microsystems, Ethernet Digital, Token passing, LAN Technologies, CSMA/CD, Access Methods, Transmission, Networks, The History of Local Area Networks, LAN