NetComm Wireless Network Device NP643 User Manual
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NP643 IEEE 802.11g PC Card Adapter
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YML786 Rev1
Preamble:
The ‘preamble’ is a sequence of bits transmitted at 1Mbps that
synchronises wireless transmission within the network. The Short
Preamble and header may be used to minimize overhead and,
thus, maximize the network data throughput. However, the Short
Preamble is supported only by the IEEE 802.11b (High- Rate)
standard and not by the original IEEE 802.11standard; meaning that
stations using Short-Preamble cannot communicate with stations
implementing the original version of the protocol.
PSDU:
PLCP service data unit
Roaming:
A LAN mobile user moves around an ESS and enjoys a continuous
connection to an Infrastructure network.
RTS: Request
To Send. An RS-232 signal sent from the transmitting station to the
receiving station requesting permission to transmit.
RTS Threshold:
Transmitters contending for the medium may not be aware of each
other. RTS/CTS mechanism can solve this “Hidden Node Problem”.
If the packet size is smaller than the preset RTS Threshold size, the
RTS/CTS mechanism will NOT be enabled.
SSID:
Service Set Identifier, which is a unique name shared among all
clients and nodes in a wireless network. The SSID must be identical
for each clients and nodes in the wireless network.
Subnet Mask:
The method used for splitting IP networks into a series of sub-
groups, or subnets. The mask is a binary pattern that is matched up
with the IP address to turn part of the host ID address field into a
field for subnets.