A walm welcome to you!!!

Let us share something worth that will help all of us to increase our knowledge orientation in the huge and ever expanding world of Networking!

I have created this blog to help each and everyone who visits this blog to get himself acquainted with new technologies, recent developments in the world of technology....

I hope you will help me share my knowledge with you....!!!!

Friday, March 2, 2012

Wireless-World without Cables

It is making me feel really great to write after changing my blog's name. I know, changing your blog's name just after a week is something that makes no sense. But, as I said, the earlier name was something that was not easier to find on the search engines. I think, most people who are technically strong know the word 'encapsulation', so there it came!!! Around the world, people are searching for the concept of encapsulation and it would now be easier to find this blog.

Ok, now let me turn to a revolutionary concept of wireless in the world of technology and networking. Actually, Wireless technology is a vast and a much vast concept and describing the whole of it in one post itself is not a good idea. If you have read my earlier posts like Virtualization, OSI etc., you can mark out that I have divided the posts into parts. Likewise, I will be doing the same for Wireless. First of all let me describe what is wireless. Being from the networking field, I will be discussing wireless in the context of networking only, if you have knowledge of other wireless technologies, it will be great if you share it on this blog.

What do you mean by the term 'Wireless'? Something where wires are absent? Yes, logically correct. Let me elaborate it more technically. Wireless is a concept where two or more devices (wireless technology enabled) are not connected physically but using medium of air and communicate using waves having specific frequency.

Wireless was discovered roughly in the year 1864. Thereafter it was developed for many devices including radio, televisions, cellular devices and now for computers etc. Wireless in the context of networking is also a very very and really very vast concept such that there are globally recognized certifications provided by giants such as Cisco. To start with, let me first of all tell you how two devices connect with each other using wireless technology. Now, in case of computers, you require a Wireless Interface Card or a Wi-fi card as a hardware device. To configure it properly and to make it work on your PC, you require suitable device drivers. These drivers are available on your PC manufacturer's website.

The most important device in the wireless technology is something called as an 'access point' or an AP.
An AP is a device that uses wireless communications to send and receive data or frames with the Wireless LAN (WLAN) enabled clients or computers.

Now, WLANs use radiated energy waves called as the radio waves to transmit data. These waves use air as a medium to get themselves transmitted and there is no need for any physical medium. The presence of walls, metal objects and other such things prove an obstruction for the waves to travel.

In a wireless environment, if more than one device sends radio waves at the same time, neither signal proves to be intelligible & hence a Half Duplex mechanism is used.
Half duplex? It is a concept in which data is transmitted in one way only and it is contrast to something called as full duplex where data is transmitted in a two way direction.

To bring standardization and to make this technology more flexible to the end consumers, many international organizations contributed to the development of WLAN Standards. Most prominent among them are the Institute of Electrical & Electronics Engineers (IEEE), Wi-fi Alliance and Federal Communications Commission (FCC).


There are different modes of 802.11 Wireless Standards. WLANs can use more than two modes-ad hoc mode and the infrastructure mode. 

With the ad-hoc mode, a wireless device can connect with other devices directly i.e. without requiring any intermediary device. I will put this concept into a diagrammatic representation, have a look at it:

Let us turn to the infrastructure mode now. Infrastructure mode uses a device called as an access point (I have discussed this terminology in the earlier paragraphs). 
Again to go into the depths of infrastructure mode, something called as 'service sets' are used. What is a service set? Simply, something that provides services in the wireless topology. The Basic Service 
Set (BSS) uses a single AP in the wireless topology while the Extended Service Set (ESS) uses multiple APs in it's topology.

The ESS WLANs allow roaming, which means that the users can move around freely inside the coverage area and stay connected to the WLANs.

In the next post, I will be going into depth of the Wireless technology


3 comments:

  1. is the access point (AP) in the nature of an intermediary device?? u mentioned ad-hoc mode doesnt require intermediary device..so here ap doesnt come in picture kya?? kinda confused about ap's role here..

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  2. absolutely right, in the ad-hoc mode that i have mentioned, AP doesn't play any role because two devices are directly connected.

    Again, if you keep ad-hoc mode aside then you require an AP as an intermediary that enable devices to connect to each other over a larger area. AP enables a person to move from one place to another easily since he is connected directly to the AP.

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  3. hey got it...:)

    ReplyDelete