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Showing posts with label Access Points. Show all posts
Showing posts with label Access Points. Show all posts

Friday, October 11, 2013

What are advantages and limitations of Wi-Fi?

The Wi-Fi has its own set of advantages and limitations. 

Advantages of WiFi
- WiFi makes the deployment of local Area Networks or LANs quite cheap.  
There are some areas where the cables cannot be installed such as in historical buildings and outdoor areas. 
- But these spaces do not have any problem in hosting a wireless LAN.  
Wireless Network adapters are being built into almost all the laptops by the manufacturers.
A basic level of service is provided at which different brands concerning and client network interfaces access points that are competing with each other can inter-operate. 
- The products that have been certified by Wi-Fi alliance show back word compatibility. 
- A standard device for WiFi will work at any place in the whole world unlike our phones. 
- The WPA2 or the WiFi protected access encryption is secure provided a condition that the pass phrase used is quite strong.  
- The new protocols use for WMM i.e., Quality of service increase the suitability of the Wi-Fi regarding its use in latency - sensitive applications. 
- WMM is a power saving mechanism that is used for extending the life of the battery. 

Limitations of WiFi
Inconsistency of the operation and spectrum assignments poses a problem worldwide.  
- The range all the WiFi networks is limited. 
- A wireless access point typically uses a stock antenna having a range of 100 m outdoors and 25m indoors.
The frequency band is a major factor for producing variations in the range.  
The range of Wi-Fi with a 2.4 ghz frequency block is better when compared with the 5.0 ghz frequency block Wi-Fi. 
- Some wireless routers come with detachable antennas. 
- These antennas can be removed for improving the range. 
- In their place upgraded antennas can be fitted. 
- The benefit of these antennas is that they have high directional gain at the remote devices. 
- The local regulations limit the maximum amount of power that can be transmitted by a Wi-Fi. 
- The power consumption of Wi-Fi is quite higher than the other standards.  
This is so because of the reach requirements of the wireless LAN applications.
- There are technologies available that provide a propagation range that is much shorter. 
- One such technology is Bluetooth and has very low power consumption.  
Other technologies such as zigbee have low power consumption, a long range but provides low data rate. 
- The most commonly used wireless encryption standard is WEP or wired equivalent privacy. 
- Even this standard has been proven to be breakable even if correct configuration is used. 
- This problem was addressed by WPA or Wi-Fi protected access standard to some extent. 
- By default the wireless access points use the encryption free mode. 
- The wireless security is disabled because of which the LAN can be openly accessed. 


Tuesday, October 8, 2013

What are uses of Wifi?

- Routers sometimes act as a Wi-Fi access point incorporating a cable modem or a DSL modem.
- These routers are installed in buildings and homes for providing Internet access and other inter networking services to the devices that in turn are connected to a either through a cable or wireless. 
- Similarly, there are routers that are powered by battery and they consist of a Wi-Fi access point and a mobile Internet radio modem. 
- Today smartphones come with this as a built-in capability.  
- However, this feature is disabled by the carriers. 
- The carriers might charge extra money for this. 
- The standalone facilities are provided by Internet packs. 
- The places where there is no network access, wifi is used. 
- Using Wi-Fi, a direct communication link between two computers can be established.  
- There is no intermediate point.  
- This type of transmission is termed as ad hoc wifi transmission. 
- This network mode is now very popular with the multi-player game consoles. Examples are:
       > Nintendo DS
       > PlayStation portable
       > Digital cameras
       > Other consumer electronic devices.


- A citywide Wi-Fi plan has been implemented by a number of the cities around the world.  
- In India, the first city to do so was Mysore.  
- The first city in the world was Jerusalem.
- The first city in United States was Sunnyvale in California to offer city-wide wifi. 
- Another type of wifi implementation is campus-wide wifi.  
- A number of colleges in United States have set up this kind of wifi network.  
The first university to have it was Carnegie Mellon University. 
- Using wifi, the local area Network can be deployed in very less cost.  
- There are places where it is not possible for the physical transmission medium such as cables to reach. 
- In such places wifi network is of crucial importance.  
- Also, wifi can be easily deployed in historical buildings and outdoor areas.  
Now, because of the increasing popularity of the Wi-Fi, the manufacturers are developing Wireless Network adapters for most of the notebooks and laptops.  
This eventually led to a fall in the price of the Wi-Fi chip set. 
- Today, the Wi-Fi chip set is economically feasible and is included in most of the devices.  
- There are many brands of client network interfaces and access-points that are competing with each other.  
- These interfaces are able to inter-operate at a basic level. 
- The Wi-Fi certification for the products is issued by wifi alliance. 
- This makes them backwards compatible with each other. 
- A standard Wi-Fi Device is supposed to work anywhere in the world. 
- The encryption standard that is considered secure is the WPA2 or wifi protected access.  
- But, this would work only if the pass phrase that is being used is strong enough. 
- The Wi-Fi has been made more suitable with the use of new protocols such as quality of service.  
- This has made wifi compatible with latency sensitive applications.  
- Nowadays, for extending battery life power saving mechanisms such as WMM are being used.  
- These are the major uses of wifi technology.
- The usage wifi has been limited because of its limited range. 
- Therefore, in order to cover up a large area several intermediate Wi-Fi access-points have to be set up. 
- The variations in the range can be produced by varying the frequency band.  
Wifi with a small frequency block works better than wifi with a larger frequency block.
- Wifi with the larger frequency blocks are optionally used. 
- The power of wifi network can be harnessed by using high gain direction antennas instead of using detachable antennas.  
- Another factor limiting the performance of wifi transmission is the local regulations. 
- Wifi also requires high power to operate upon. 
- This is a cause of concern for the devices' batteries.


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