Netgear MA111v1 MA111v1 User Manual - Page 12

Authentication and WEP Encryption The absence of a physical connection between nodes makes the wireless links vulnerable to information theft. To provide a certain level of security, IEEE 802.11 standard has defined two types of authentication methods, Open System and Shared Key. Open System authentication is a null algorithm. Shared Key authentication is an algorithm where both the transmitting node and the receiving node share an authentication key to perform a checksum on the original message. By default, IEEE 802.11 wireless devices operate in an open system network. Wired Equivalent Privacy (WEP) data encryption is utilized when the wireless nodes or access points are configured to operate in Shared Key authentication mode. There are three shared key methods implemented in NETGEAR 802.11b solutions: the standard based 64-bit WEP data encryption and 128-bit WEP data encryption. The 64-bit WEP data encryption method allows for a five-character (40 bits) input. Additionally, 24 factory-set bits are added to the 40-bit input to generate a 64-bit encryption key. (The 24 factory-set bits are not user configurable.) This encryption key will be used to encrypt/decrypt all data transmitted via the wireless interface. Some vendors may refer to the 64-bit WEP data encryption as 40-bit WEP data encryption since the user configurable key used in the encryption process is only 40 bits wide. The 128-bit WEP data encryption method consists of 104 configurable bits. Similar to the 64-bit WEP data encryption method, the remaining 24 bits are factory set and not user configurable. Encryption # of Hexadecimal Example of Hexadecimal Key Size Digits Key Content 64-bits (24+40) 10 4C72F08AE1 128-bit (24+104) 26 4C72F08AE19D57A3FF6B260037 Wireless Channel Selection 802.11b IEEE 802.11b wireless nodes communicate with each other using radio frequency signals in the ISM (Industrial, Scientific, and Medical) band between 2.4 GHz and 2.5 GHz. Neighboring channels are 5 MHz apart. However, due to spread spectrum effect of the signals, a node sending signals using a particular channel will utilize frequency spectrum 12.5 MHz above and below the center channel frequency. As a result, two separate wireless networks using neighboring channels (for example, channel 1 and channel 2) in the same general vicinity will interfere with each other. 21 Applying two channels that allow the maximum channel separation will decrease the amount of channel cross talk, and provide a noticeable performance increase over networks with minimal channel separation. Channel Center Frequency Frequency Spread 1 2412 MHz 2399.5 MHz - 2424.5 MHz 2 2417 MHz 2404.5 MHz -2429.5 MHz 3 2422 MHz 2409.5 MHz -2434.5 MHz 4 2427 MHz 2414.5 MHz -2439.5 MHz 5 2432 MHz 2419.5 MHz - 2444.5 MHz 6 2437 MHz 2424.5 MHz -2449.5 MHz 7 2442 MHz 2429.5 MHz -2454.5 MHz 8 2447 MHz 2434.5 MHz - 2459.5 MHz 9 2452 MHz 2439.5 MHz -2464.5 MHz 10 2457 MHz 2444.5 MHz -2469.5 MHz 11 2462 MHz 2449.5 MHz - 2474.5 MHz 12 2467 MHz 2454.5 MHz - 2479.5 MHz 13 2472 MHz 2459.5 MHz - 2484.5 MHz Note: The available channels supported by the wireless products in various countries are different. For example, Channels 1 to 11 are supported in the U.S. and Canada, and Channels 1 to 13 are supported in Europe and Australia. 22