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WLAN: Wireless LAN by IEEE 802.11, 802.11a, 802.11b, 802.11g

The Wireless Local Area Network (WLAN) technology is defined by the IEEE 802.11 family of specifications. There are currently four specifications in the family: 802.11, 802.11a, 802.11b, and 802.11g. All four use the Ethernet protocol and CSMA/CA (carrier sense multiple access with collision avoidance instead of CSMA/CD) for path sharing.

Wi-Fi Wireless LAN Security Problems and Solutions

While the wireless LAN provides many conveniences in today’s communication world, it also introduces unique security challenges, compare with the traditional wired network.  The early version of the Wi-Fi technology, IEEE 802.11b, tried to overcome the security issue by devising a user authentication and data encryption system known as Wired Equivalent Privacy, or WEP. Unfortunately, some compromises that were made in developing WEP have resulted in it being much less secure than intended.

ISO Application Layer Protocols

This section list articles regarding the appilication layer protocols defined by the International Standard Organization (ISO).

L2TP / PPTP Virtual Private Network (VPN)

The Layer 2 Tunneling Protocol (L2TP), an IETF standard based on the Mirosoft Point to Point Tunneling Protocol (PPTP) and the Cisco Layer 2 Forward protocol (L 2F ), provides remote users encrypted, multi-protocol dial up access to a corporate network over the Internet. PPTP and L2TP are the layer 2 VPN technologies from CPE (customer premise equipment) to CPE.

WDM: Wavelength Division Multiplex and Multiplexer

Wavelength Division Multiplexing (WDM) is a technique that multiple signals are carried together as separate wavelengths (color) of light in a multiplexed signal. WDM is used in optical fiber networks. WDM and FDM (Frequency Division multiplex) are both based on the same principles but WDM applies to wavelengths of light in optical fiber while FDM is used in electrical analog transmission. A WDM optical system using a diffraction grating is completely passive, unlike electrical FDM, and thus is highly reliable.

How to detect an illegal sniffing tool and defend its harm on a network?

Network sniffing tool, also called Protocol Analyzer, Packet Analyzer, Sniffer, Network packet analyzer etc. is a program and/or device that monitors analyzes data traveling over a network. Network sniffing tools can be used both for legitimate network management functions and for stealing information off a network. Unauthorized network sniffing tools can be extremely dangerous to a network's security because they are virtually impossible to detect and can be inserted almost anywhere. This makes them a favorite weapon in the hacker's arsenal.

Ping: Packet Internet Groper

Ping is a popular TCP/IP network utility using the Internet Control Message Protocol (ICMP) to determine the availability and responsiveness of network hosts. A system administrator uses the Ping tool to see if a computer is operating as wells as if network connections are intact.

ERP System Components and Implementation Process

Enterprise Resource Planning (ERP) systems integrate all data and processes of an organization into a unified system. A typical ERP system will use multiple components of computer software and hardware to achieve the integration. A key ingredient of most ERP systems is the use of a unified database to store data for the various system modules. In the absence of an ERP system, a large organization may find itself with many software applications that do not talk to each other and do not effectively interface.

Wi-Fi: Wireless Fidelity and Wi-Fi Network

Wi-Fi networks use radio technologiesdefined by IEEE 802.11b, 802.11a, 802.11g or 802.11n (and 802.11y) . A Wi-Fi network can be used to connect computers to each other, to the Internet, and to wired networks using IEEE 802.3 or Ethernet. Wi-Fi networks operate in the unlicensed 2.4 and 5 GHz radio bands, with an 11 Mbps (802.11b) or 54 Mbps (802.11a or 802.11g) data rate or with products that contain both bands (dual band), so they can provide real-world performance similar to the basic 10BaseT wired Ethernet networks used in many offices.

TDM: Time Division Multiplex and Multiplexer

Time Division Multiplex (TDM) is a technique of transmitting multiple digitized data, voice, and video signals simultaneously over one communication media by interleaving pulses representing bits from different channels or time slots. The basic channel bandwidth in the telecommunication is DS0, which channel width of 64kbps.

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