NETGEAR MA 301, Справочное руководство

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Service Set Identification (SS ID)
The Service Set Identification (SS ID) is a thirty-two alphanumeric character (maximum) string
identifying the wireless local area network. Some vendors refer to the SS ID as network name. For
stations to communicate with each other, all stations must be configured with the same SS ID.
A wireless LAN consisting of nodes operating in ad hoc configuration without an access point is called a
Basic Service Set (BSS). All nodes in a BSS must use the same Basic Service Set ID (BSS ID).
In an infrastructure configuration with access points, multiple BSS can be configured to form an Extended
Service Set (ESS). In this configuration, the access points are configured with the same Extended Service
Set ID (ESS ID). Wireless clients configured with the same ESS ID can freely roam from one Access
Point domain to another and still maintain seamless connection to the network
Authentication and WEP Encryption
The absence of a physical connection between nodes makes the wireless links vulnerable to information
theft. To provide 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 two shared key methods implemented
in most commercially available products, forty-bit WEP data encryption and 128-bit WEP data
encryption.
The forty-bit WEP data encryption method, allows for a five-character (forty-bit) input. Additionally, 24
factory-set bits are added to the forty-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 forty-bit WEP data encryption as 64-bit WEP data
encryption since the actual encryption key used in the encryption process is 64 bits wide.
The 128-bit WEP data encryption method consists of 104 configurable bits. Similar to the forty-bit WEP
data encryption method, the remaining 24 bits are factory set and not user configurable. Some vendors
allow passphrases to be entered instead of the cryptic hexadecimal characters to ease encryption key entry.