Wireless broadband (WiBB) a networking technology designed to impart highspeed Internet and data service through wireless networks. Wireless broadband may be delivered through wireless local area networks (WLANs) or wide area networks (WWANs).Similar to other wireless services, wireless broadband can be either fixed or mobile.Features of WiBBWiBB is similar to wired broadband service since they connect to an internet backbone, with the difference that they use radio waves instead of cables to connect to the last mile of the network.The range of most broadband wireless access (BWA) services varies around 50 km from the transmitting tower.Download speeds provided by some ... Read More

The Advanced Encryption Standard, or AES, is an encryption standard established in 2001 by the National Institute of Standards and Technology (NIST) of USA. It is implemented worldwide both in hardware and software to encrypt sensitive data. AES finds wide usage while transmitting data over computer networks, particularly in wireless networks.Features of AESAES is a subset of Rijndael block cipher.It is a successor of Data Encryption Standard (DES) and is stronger and faster than DES.It is a symmetric key symmetric block cipher.It operates on 128-bit (16 bytes) data.The cipher key may be of 128, 192 or 256 bits.All computations are ... Read More

Wired Equivalent Privacy (WEP) is a security standard for wireless networks or WiFi. It was a part of the original IEEE 802.11 protocol. As wireless networks transmit data over radio waves, eavesdropping on wireless data transmissions is relatively easier than in wired networks connected by cables. WEP aims to provide the same level of security and confidentiality in wireless networks as in wired counterparts.Features of WEPWEP was introduced as a part of IEEE 802.11 standard in 1997.It was available for 802.11a and 802.11b devices.WEP uses encryption of data to make it unrecognizable to eavesdroppers.It uses RC4, a stream cipher, for ... Read More

Wi-Fi Protected Access (WPA) and Wi-Fi Protected Access 2 (WPA2) are security standards to protect network stations connected to WiFi networks. They were developed by WiFi Alliance for delivering sophisticated data encryption technologies and improved user authentication than the pre-existing Wired Equivalent Privacy (WEP).WiFi Protected Access (WPA)Wi-Fi Protected Access (WPA) was supported in IEEE 802.11i wireless networks and was proposed in 2004. It was backward-compatible with the existing WEP that led to its rapid, hassle-free adoption.The encryption method adopted in WPA is the Temporal Key Integrity Protocol (TKIP). TKIP includes per-packet key, integrity check, re-keying mechanism. It dynamically generates an ... Read More

IEEE 802.11 standard, popularly known as WiFi, lays down the architecture and specifications of wireless LANs (WLANs). WiFi or WLAN uses high frequency radio waves for connecting the nodes.There are several standards of IEEE 802.11 WLANs. The prominent among them are 802.11, 802.11a, 802.11b, 802.11g, 802.11n and 802.11p. All the standards use carrier-sense multiple access with collision avoidance (CSMA/CA). Also, they have support for both centralised base station based as well as ad hoc networks.IEEE 802.11IEEE 802.11 was the original version released in 1997. It provided 1 Mbps or 2 Mbps data rate in the 2.4 GHz band and used ... Read More

The IEEE 802.11 standard, lays down the architecture and specifications of wireless local area networks (WLANs). WLAN or WiFi uses high frequency radio waves instead of cables for connecting the devices in LAN. Users connected by WLANs can move around within the area of network coverage.The 802.11 MAC sublayer provides an abstraction of the physical layer to the logical link control sublayer and upper layers of the OSI network. It is responsible for encapsulating frames and describing frame formats.MAC Sublayer Frame Structure of IEEE 802.11The main fields of a frame in WLANs as laid down by IEEE 802.11 are as ... Read More

eval is a builtin command of the Bash shell which concatenates its arguments into a single string. Then it joins the arguments with spaces, then executes that string as a bash command. Below is an example of how it works.eval exampleIn the below example we take a string which has some Unix commands built into it and then apply eval to it.$ var="echo n" $ echo $var $ eval $varRunning the above code gives us the following result −echo n nAs you can see, when eval is applied the variable expands it gets executed as a command and no longer ... Read More

A system call is the fundamental interface between an application and the Linux kernel. When a Unix/Linux program does a file I/O, network data transfer or invokes some process which directly or indirectly interact with the low level instructions, then system call is involved. Making these calls usually involves using a library called glibc which contains the functions.ExamplesBelow is a list of some frequently used system calls and their purpose.Sr.NoSystem CallPurpose1chmodchange permissions of a file2chdirchange working directory3forkcreate a child process4unlinkdelete a name and possibly the file it refers toA systems programmer writes program that will not directly make the systems ... Read More

Often it is a requirement to read each of the line from a file using a bash script. There are various approaches to read the lines form a file. In the below example we have first described how to create a sample file and then run a script reading that sample file.Create a file to Read# Open vi Editor vi a_file.txt # Input the below lines Monday Tuesday Wednesday Thursday Friday Saturday Sunday # cat the file cat a_file.txtRunning the above code gives us the following result −Monday Tuesday Wednesday Thursday Friday Saturday SundayUsing Do-WhileIn this approach we use a ... Read More

When we transfer files between Windows and Unix systems, often we come across with issue relating to the end of line character. This is because the EOL character in windows is not recognized as a EOL character in Unix. SO to fix this issue when a file is transferred from Windows to Unix we need to follow one of the below methods.Using dos2unixThe dos2unix command is used to convert the EOL character of windows platform to Unix platform. Most of the Unix system comes with this command pre-installed. Below we see how we can convert the file itself or save ... Read More