olhon.info Technology Wireless Networking Tutorial Pdf


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Wireless Networking. Technology. From Principles to Successful Implementation. Steve Rackley. AMSTERDAM • BOSTON • HEIDELBERG • LONDON. INTRODUCTION TO WIRELESS. NETWORKS. Up to a point, it's quite possible to treat your wireless network as a set of black boxes that you can turn on and. tutorial helps to develop an overview on the existing trends of wireless .. communication with other wired and wireless networks as well as support for.

Wireless Networking Tutorial Pdf

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Introduction. Wireless technology has helped to simplify networking by enabling multiple computer users to simultaneously share resources in a home or. IEEE Wireless Personal Area Networks (WPAN). • UWB (Multi-band OFDM). IEEE Wireless Local Area Networks (WLAN). Wireless Network. Design & Architecture. Matt Peterson. Bay Area Wireless Users Group. Rajendra Poudel. Nepal Wireless/ENRD.

What is different about the way you use each of these? Wi-Fi Signals When building a network, you will be using Wi-Fi technology, which has some unique characteristics you will need to know. There are two types of Wi-Fi signal, based on the frequencies they use: 2. Many devices use it, so the signals can become more crowded and interfere with each other.

It can pass through walls and windows fairly well. It cannot pass through walls and windows as well as the 2. Each frequency band used in Wi-Fi is divided up into multiple "channels". Each channel is similar to rooms at a party - if one room is crowded it is hard to carry on a conversation.

You can move to the next room, but that might get crowded as well. As soon as the building is full, it becomes difficult to carry on a conversation at the party. If you are setting up a mesh network -- all of the mesh links will need to be on the same channel. The available channels vary depending on where you are in the world.

Learning Wireless Networking

For example, in the United States channels 12, 13 and 14 are not allowed for Wi-Fi, as those frequencies are used by TV and satellite services. If you are building networks in the United States, you can only use channels 1 through In the rest of the world, channels 1 through 13 are generally usable, and in a few places channel 14 is available.

Despite that, the best channels in the United States and most of the world to use for 2.

This will minimize interference caused by partially overlapping Wi-Fi signals: You could use other sets of Wi-Fi channels, as long as they are 5 channels apart - for instance 3, 8 and This may not be optimal though, as channels 1 and 2 would be unused, and in many places in the world channel 13 is not available.

Wherever you are, try and check what channels are most in use, and plan your network to use a channel that doesn't overlap.

How to Hack WiFi (Wireless) Network

This may not always be true -- more and more wireless equipment is starting to use the 5GHz In the United States, only channels available for building mesh networks are 36, 40, 44, 48, , , , , and The best place to check what is allowed in your area is online.

Links are provided in External Resources at the end of this document. When setting up your wireless network, you will need to think about what frequency band to use, and what channel to use.

Power and Receiver Sensitivity Many people want to know how far wireless signals will go. Knowing this is important for planning a network, as the power of the routers will affect the design of the network, and how much equipment is needed. Different Wi-Fi routers can have very different power levels.

Some are much stronger: they have more speaking or transmitting power than others. Some are very good listeners: they have what is called a better receive sensitivity. These two elements define how well wireless devices will connect, and how far away a receiving Wi-Fi router can be.

Topics covered in this tutorial

In some cases, usually with more business or professional oriented equipment you can find the information for transmit power and receive sensitivity. For instance, a light bulb might be 40 watts. A router will have an output power of mW, which is times less! A dBm is a relative measurement using logarithms.

One milliwatt is 0 dBm. This is the scale that many network designers use to calculate if longer wireless links will work. A few examples of the transmit power levels in common Wi-Fi hardware is below: 10mW 10dBm : Laptop or smartphone, or very low cost Wi-Fi router.

About 25 to 50 meters mW 20dBm : Indoor home or office router. About 50 to meters mW 20dBm : Outdoor sector router.

About 10 to 20 kilometers or more Wireless transmitter power is only one half of the connection. The stream cipher input is made up of an initial value IV and a secret key. The length of the initial value IV is 24 bits long while the secret key can either be 40 bits or bits long.

The total length of both the initial value and secret can either be 64 bits or bits long. The lower possible value of the secret key makes it easy to crack it. Weak Initial values combinations do not encrypt sufficiently.

This makes them vulnerable to attacks. WEP is based on passwords; this makes it vulnerable to dictionary attacks.

Keys management is poorly implemented. Changing keys especially on large networks is challenging. WEP does not provide a centralized key management system.

It is used to encrypt data on It uses temporal keys to encrypt packets. WPA Weaknesses The collision avoidance implementation can be broken It is vulnerable to denial of service attacks Pre-shares keys use passphrases. Weak passphrases are vulnerable to dictionary attacks.

How to Crack Wireless Networks WEP cracking Cracking is the process of exploiting security weaknesses in wireless networks and gaining unauthorized access.

There are basically two types of cracks namely; Passive cracking— this type of cracking has no effect on the network traffic until the WEP security has been cracked.

It is difficult to detect.

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Active cracking— this type of attack has an increased load effect on the network traffic. It is easy to detect compared to passive cracking.

It is more effective compared to passive cracking. It is an implementation of the FMS attack. It has its own key generator and implements packet filters. Short passphrases are vulnerable to dictionary attacks and other attacks that can be used to crack passwords.

The following tools can be used to crack WPA keys. CowPatty— this tool is used to crack pre-shared keys PSK using brute force attack.

Denial of Service Attack— the main intent of this attack is to deny legitimate users network resources. FataJack can be used to perform this type of attack.Wireless clients can be mobile devices such as laptops, personal digital assistants , IP phones and other smartphones , or non-portable devices such as desktop computers , printers, and workstations that are equipped with a wireless network interface.

Which two of the following are unlicensed frequency bands used in the United Stated? The following tools can be used to crack WPA keys.

It has its own key generator and implements packet filters. One of these problems is interference, which is discussed at length in Chapter 5, "Antennae Communications.

The bridge acts as the connection point to the Wireless LAN. IT and Hardware. With RF, the goal is to send as much data as far as possible and as fast as possible.