09-05-2014, 03:21 PM
WIRELESS PACKET SNIFFER AND ANALYZER
WIRELESS PACKET .doc (Size: 50 KB / Downloads: 10)
INTRODUCTION:
PURPOSE:
To develop an application that can intercept the log traffic passing over a digital network. As data streams flow across the network the sniffer captures each packet and if needed decodes the packet’s raw data showing the values of various fields in the packet and analyzes its content according to the appropriate specifications. Following are the purposes that a protocol analyzer can serve:
Diagnosing and investigating network problems
Monitoring network usage, activity, and security
Discovering network misuse, vulnerabilities and attack attempts
Identifying configuration issues and network bottlenecks
SCOPE
Depending on the network structure one can capture traffic from a single machine within the network, for network monitoring purposes; it may also be desirable to monitor all the data packets in a LAN by using a network switch with a monitoring port.
BACKGROUND:
IEEE 802.11:
The IEEE 802.11 is a set of physical layer standards for implementing wireless local area network (WLAN) computer communication. There is various wireless networking protocols like 802.11a, 802.11b, 802.11g, 802.11n. But among these the most popular are 802.11b and 802.11g protocols. The modulation used in 802.11 is phase shift keying (PSK) but 802.11a uses OFDM (orthogonal frequency division multiplexing) for high data speed (up to 54 mbps) but mainly Wi-Fi communication takes place at 6-24 mbps. All the 802.11 standards uses the Ethernet protocol and CSMA/CA (carrier sense multiple access with collision avoidance) for path sharing.
The IEEE 802.11 standard defines a MAC protocol and three possible physical layer interfaces, these are FHSS frequency hopping spread spectrum, DSSS direct sequence spread spectrum, IR infra-red.