What is LAN, WLAN, WAN, MAN, SAN, CAN, PAN and GAN ?

Computer networks are bunch of interconnected PC or computers that facilitate the exchange of data or some other purposeful work. The first computer network to be designed was the "Advanced Research Projects Agency Network" (ARPANET) for the United States Department of Defense in the late 1960s and early 1970s. From then on, numerous new network technologies have been developed.

Computer networks can be classified into different types based on their scale of operation. They include:

• LAN: Local Area Networks cover a small physical area, like a home, office, or a small group of buildings, such as a school or airport.


• WLAN: Wireless Local Area Networks enable users to move around within a larger coverage area, but still be wirelessly connected to the network.


• WAN: Wide Area Networks cover a broad area, like communication links that cross metropolitan, regional, or national boundaries. The Internet is the best example of a WAN.


• MAN: Metropolitan Area Networks are very large networks that cover an entire city.


• SAN: Storage Area Networks help attach remote computer storage devices, such as disk arrays, tape libraries, and optical jukeboxes, to servers in such a manner that that they appear to be locally attached to the operating system.


• CAN: Controller Area Networks allow micro controllers and devices to communicate with each other without a host computer.


• PAN: Personal Area Networks are used for communication among various devices, such as telephones, personal digital assistants, fax machines, and printers, that are located close to a single user.


• GAN: Global Area Networks support mobile communications across an arbitrary number of wireless LANs and satellite coverage areas.


• INTERNETWORK: Internetworking is the process of connecting two or more distinct computer networks or network segments through a common routing technology.

Computer networks are an integral part of our lives. It is only because of networking that telephones, televisions, radios, and the Internet are at our fingertips.

Wireless Routing Protocol

The Wireless Routing Protocol (WRP) is a proactive unicast routing protocol for mobile ad-hoc networks (MANETs). WRP uses an enhanced version of the distance-vector routing protocol. Because of the mobile nature of the nodes within the MANET, the protocol introduces mechanisms which reduce route loops and ensure reliable message exchange.
WRP is a distance vector routing protocol. Each node maintains 4 tables:
Distance table
Routing table
Link cost table
Message Retransmission List table


The wireless routing protocol (WRP), similar to DSDV, inherits the properties of the distributed Bellman-Ford algorithm. To counter the count-to-infinity problem and to enable faster convergence, it employs a unique method of maintaining information regarding the shortest distance to every destination node in the network and the penultimate hop node on the path to every destination node. Since WRP, like DSDV, maintains an up-to-date view of the network, every node has a readily available route to every destination node in the network. It differs from DSDV in table maintenance and in the update procedures. While DSDV maintains only one topology table, WRP uses a set of tables to maintain more accurate information. The tables that are maintained by a node are the following: distance table (DT), routing table (RT), link cost table (LCT), and a message retransmission list (MRL).

The DT contains the network view of the neighbors of a node. It contains a matrix where each element contains the distance and the penultimate node reported by a neighbor for a particular destination. The RT contains the up-to-date view of the network for all known destinations. It keeps the shortest distance, the predecessor node (penultimate node), the successor node (the next node to reach the destination), and a flag indicating the status of the path. The path status may be a simple path (correct), or a loop (error), or the destination node not marked (null). The LCT contains the cost (e.g., the number of hops to reach the destination) of relaying messages through each link. The cost of a broken link is infinity. It also contains the number of update periods (intervals between two successive periodic updates) passed since the last successful update was received from that link. This is done to detect links breaks. The MRL contains an entry for every update message that is to be retransmitted and maintains a counter for each entry. This counter is decremented after every retransmission of an update message. Each update message contains a list of updates. A node also marks each node in the RT that has to acknowledge the update message it transmitted. Once the counter reaches zero, the entries in the update message for which no acknowledgments have been received are to be retransmitted and the update message is deleted. Thus, a node detects a link break by the number of update periods missed since the last successful transmission. After receiving an update message, a node not only updates the distance for transmission neighbors but also checks the other neighbors’ distance, hence convergence is much faster than DSDV.

Sources:http://en.wikipedia.org/wiki/Wireless_Routing_Protocol

How to Extend Wireless Range

Maximizing the signal of a wireless network is always a big advantage to a home, business establishment, or workplace. There are many ways of boosting wireless range. Some may require something as simple as relocating the wireless router, while some would need special equipment. One or a combination of these methods will hopefully help extend network range enough to cover an entire home, office, or establishment.

Materials Needed:
- wireless router
- hi-gain antenna (optional)
- USB network adapter (optional)
- wireless repeater (optional)
Step 1
Try relocating the router. Ideally, the router should be placed at the center of the area for maximum coverage in all directions. Also, thick metal and concrete, as well as floors may interfere with the signal of the router so try placing the unit away from these obstructions. Elevating the unit onto a table or mounting it on a wall may also help boost the signal.

Step 2
Try to gauge if the signal has increased by referring to the Wi-Fi client’s signal meter.

Step 3
Try changing the orientation of the router’s antennas (horizontal, vertical, at a certain angle) to see which direction works best to intensify the signal.

Step 4
Go to the wireless router’s configuration page to change channels. Changing the wireless channel, much like fiddling with the dial of a radio to find the best signal, may also help in choosing a channel that is free of interference.

Step 5
Most antennas that come with the router are omni-directional so they broadcast in equal intensity around the router. This will prove inefficient if the router is near an outside wall since half of the signal will go to a place outside the needed area. If this is the case, consider upgrading to a hi-gain antenna. This kind of antenna will concentrate the wireless signal toward only one direction, maybe the area where the router power is most needed.

Step 6
Adding a wireless repeater is one very common way of increasing signal strength. Placing the repeater halfway from the computer and the router will instantly boost the wireless signal. Choose a repeater from the same producer of the router if possible, as hardware coming from the same manufacturers generally work better together.

Step 7
Upgrading the wireless router may prove to be more costly but it is the surest way to actually boost wireless signal. The best in the market, according to most online reviews, is the 802.11n so far. It has been said that this model’s signal provides better range as well as stability. It has also been observed that it crashes less frequently than other models.

How to Encrypt a Wireless Router

A wireless network deployed without adequate encryption is similar to a house without front door with a welcome mat saying thieves are welcomed here at any time. The increasing popularity of Wireless Fidelity (Wi-Fi) networks also led to a need for more reliable protection mechanism which prevents the hijacking of the Internet connection for authorized users of the wireless network. Unfortunately, majority of novice computer owners opt to forego of the process of encrypting the broadcasting of their wireless routers because of the perceived complexity associated with the procedure. This is a dangerous practice because it allows an unhampered access not only to the broadband connection but possibly to the resources of the network clients.

Materials Needed:
- Wireless router
- computer
- Internet connection
- Web browser
Step 1
The process of encrypting the digital signals of the wireless router is not as complicated as it seems. To lock down the router broadcast, open the Web browser and type the IP address of the wireless router in the address page. Possible addresses are 192.168.1.1, 192.168.0.1, and 192.168.2.1 among others depending on the device’s manufacturer. Consult your router manual for verification.
Step 2
Entering the correct address will bring up the Administrator login screen for the router. Unless previously modified, possible default usernames are admin, root, or simply a blank box. The possible passwords would be admin or just leaving it blank. The default username and password should be in the device documentation.
Step 3
After successfully entering the correct username and password, the Web Administration Page will be displayed to the user. This is where the encryption of the broadcast will be done.
Step 4
Click on the “Wireless” section of the router configuration page. Choose the section for the “Wireless Security” option.
Step 5
Under the “Security Mode” option, click the dropdown list to select from the possible choices for encryption mode. Each router supports a different range of security methods. More common choices would be WPA (further divided into Personal and Pre-Shared key) and WEP.
Step 6
After choosing the preferred security method, choose the “Wireless Encryption Level” which is normally 64- or 128-bits. The higher the number of bits, the more secured the encryption level is.
Step 7
In the Passphrase field, type a reference text that you can remember. Click on the “Generate” button which will generate a corresponding key based on the Wireless Encryption Level. This code serves as the password for all wireless devices attempting to access the network.
Step 8
Click on the “Save Changes” button to implement the new configuration. Test the broadcast encryption by attempting to connect your wireless device without specifying the network password. The connection should be denied.
Step 9
Repeat the same connection process but this time, type in the generated network key. Click on the “Connect” button. The wireless device should be able to connect to the network. Select the option to save the network key to eliminate the need to type it in at every connection attempt.

Sources: http://www.liutilities.com/how-to/encrypt-a-wireless-router/

What is WiFi ? what is different type of wirless network

Wireless, or WiFi, technology is another way of connecting your computer to the network using radio frequency and no network cables.

Wireless works similarly to cordless phones; they transmit data from one point to another through radio signals. But wireless technology also requires that you be within the wireless network range area to be able to connect your computer. There are three different types of wireless networks:

Wireless Local Area Network (WLAN): WLAN are wireless networks that use radio waves. The backbone network usually uses cables, with one or more wireless access points connecting the wireless users to the wired network. The range of a WLAN can be anywhere from a single room to an entire campus.

Wireless Personal Area Network (WPAN): WPANs are short-range networks that use Bluetooth technology. They are commonly used to interconnect compatible devices near a central location, such as a desk. A WPAN has a typical range of about 30 feet.

Wireless Wide Area Networks (WWAN): WWANs are created through the use of mobile phone signals typically provided and maintained by specific mobile phone (cellular) service providers. WWANs can provide a way to stay connected even when away from other forms of network access. Also, be aware that additional charges are often associated with the usage of WWANs in some locations

10 tips for improving your wireless network

If Windows ever notifies you about a weak signal, it probably means your connection isn't as fast or as reliable as it could be. Worse, you might lose your connection entirely in some parts of your home. If you're looking to improve the signal for your wireless network, try some of these tips for extending your wireless range and improving your wireless network performance.

Position your wireless router (or wireless access point) in a central location:

When possible, place your wireless router in a central location in your home. If your wireless router is against an outside wall of your home, the signal will be weak on the other side of your home. Don't worry if you can't move your wireless router, because there are many other ways to improve your connection.

Move the router off the floor and away from walls and metal objects (such as metal file cabinets):

Metal, walls, and floors will interfere with your router's wireless signals. The closer your router is to these obstructions, the more severe the interference, and the weaker your connection will be.

Replace your router's antenna:

The antennas supplied with your router are designed to be omni-directional, meaning they broadcast in all directions around the router. If your router is near an outside wall, half of the wireless signals will be sent outside your home, and much of your router's power will be wasted. Most routers don't allow you to increase the power output, but you can make better use of the power. Upgrade to a hi-gain antenna that focuses the wireless signals only one direction. You can aim the signal in the direction you need it most.

Replace your computer's wireless network adapter:

Wireless network signals must be sent both to and from your computer. Sometimes, your router can broadcast strongly enough to reach your computer, but your computer can't send signals back to your router. To improve this, replace your laptop's PC card-based wireless network adapter with a USB network adapter that uses an external antenna. In particular, consider the Hawking Hi-Gain Wireless USB network adapter, which adds an external, hi-gain antenna to your computer and can significantly improve your range.

Add a wireless repeater

Wireless repeaters extend your wireless network range without requiring you to add any wiring. Just place the wireless repeater halfway between your wireless access point and your computer, and you'll get an instant boost to your wireless signal strength. Check out the wireless repeaters from ViewSonic, D-Link, Linksys, and Buffalo Technology.

Reduce wireless interference:

If you have cordless phones or other wireless electronics in your home, your computer might not be able to "hear" your router over the noise from the other wireless devices. To quiet the noise, avoid wireless electronics that use the 2.4GHz frequency. Instead, look for cordless phones that use the 5.8GHz or 900MHz frequencies.

Update your firmware or your network adapter driver:

Router manufacturers regularly make free improvements to their routers. Sometimes, these improvements increase performance. To get the latest firmware updates for your router, visit your router manufacturer's Web site.

Similarly, network adapter vendors occasionally update the software that Windows uses to communicate with your network adapter, known as the driver. These updates typically improve performance and reliability. To get the driver updates, do the following:
Windows Vista users: Click the Start menu, click All Programs, and then click Windows Update. In the left pane, click Check for updates, and then wait while Windows looks for the latest updates for your computer. Install any updates relating to your wireless network adapter.
Windows XP users: Visit Microsoft Update, click Custom, and then wait while Windows looks for the latest updates for your computer.

Pick equipment from a single vendor:

While a Linksys router will work with a D-Link network adapter, you often get better performance if you pick a router and network adapter from the same vendor. Some vendors offer a performance boost of up to twice the performance when you choose their hardware: Linksys has the SpeedBooster technology, and D-Link has the 108G enhancemen.

Source:http://www.microsoft.com/athome/setup/wirelesstips.aspx

How to Secure Your Wireless Network

Wireless Network :- it is a network which is set up by radio signal frequency. wireless network cummnicate among computers and other network devices.It also known as Wifi network or WLAN.this types of networking is increaseing day by day nowadays due to easily in setup.The main advantage is also that no cabling involved with it.we can connect many computer in anywhere in your house and office without any wires.In wireless networking computer send the binary data and it will be encoded to radio frequency and transmitted through wireless router.The network computer get the radio frequency data in binary data after decode the signal.

Before installing a wireless router we have known the requirement and how to setup.One wireless support only one WLAN.We keep in mind that setup of WLAN installation as simple as possible.Most probably try to install our wireless router in a central location within the home and office.Keeps your computer closer to your Wifi networking works.In Installation we have to give the name of network,in wi-fi networking, the netowrk name is often called the SSID.We shared same SSID with all router and computer on the WLAN.

If our Wireless networking instalation is done,we have to keep in mind that,all works not done here.We have to more take some precaution regarding to secure oue wireless networking.Some don't know about it, other just ignore it.if we have an unsecured wireless network the outsider computer people connect to your network, use your connection for downloading illegal stuffs. We takes Example in Xp how we check our unsecured network. Go to 'network connection' and search wireless networks in range.in that windows we should be able to see whether the your wireless network "NAME" to is secure or not.In this you have check the WPA or WEP encryption method also.( Right click on the network, select 'Properties' and then look for 'Encryption type' we have to change this Encryption type or password once in a week.Without Encryption and other protectives measure, any one can use you network and see our wi-fi traffic.we should keep ON the firewall build into your router to prevents from hackers on the internet from getting access code to our Computer and also should run software firewalls on individual PCs on our network.Some goods software also available on net to prevent our wi-fi network like Zone Alarm which is easily available on net free.