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quiet and two devices access the media at exactly the same time, their signals collide. When the
collision is detected, they both back off and wait for a random amount of time before retrying.
DHCP:
Dynamic Host Configuration Protocol, which is a protocol that lets network administrators
manage and allocate Internet Protocol (IP) addresses in a network easily. Every computer must have
an IP address in order to communicate with each other in a TCP/IP-based network. Without DHCP,
each computer must be entered the IP address manually. DHCP enables the network administrators to
assign the IP from a central location and each computer receives an IP address upon connected to the
network.
DSSS:
Direct Sequence Spread Spectrum. DSSS generates a redundant bit pattern for each bit to be
transmitted. This bit pattern is called a chip (or chipping code). The longer the chip, the greater the
probability that the original data can be recovered. Even if one or more bits in the chip are damaged
during transmission, statistical techniques embedded in the radio can recover the original data without
the need for retransmission. To an unintended receiver, DSSS appears as low power wideband noise
and is rejected (ignored) by most narrowband receivers.
Dynamic IP Address:
An IP address that is assigned automatically to a client station in a TCP/IP
network by a DHCP server.
Encryption:
A security method that uses a specific algorithm to alter the data transmitted, and thus
prevent others from knowing the information transmitted.
ESS:
ESS stands for
“
Extended Service Set
”
. More than one BSS is configured to become an
Extended Service Set. WLAN mobile users can roam between different BSSs in an ESS.
ESSID:
The unique identifier that identifies the ESS. In infrastructure mode, the stations use the same
ESSID as AP
’
s to communicate.
Ethernet:
A popular local area data communications network, originally developed by Xerox Corp.,
Ethernet operates in a 10/100 Mbps base transmission rate, using a shielded coaxial cable or over
shielded twisted pair telephone wire.
Fragmentation:
When transmitting a packet over a network medium, sometimes the packet is broken
into several segments, if the size of packet exceeds that allowed by the network medium.
Fragmentation Threshold:
The Fragmentation Threshold defines the number of bytes used for the
fragmentation boundary for directed messages. The purpose of "Fragmentation Threshold" is to
increase the transfer reliability thru cutting a MAC Service Data Unit (MSDU) into several MAC Protocol
Data Units (MPDU) in smaller size. The RF transmission can not allow to transmit too big frames due to
the heavy interference caused by the big size of transmission frame. But if the frame size is too small, it
will create the overhead during the transmission.
Gateway:
a device that interconnects networks with different, incompatible communication protocols.
HEX:
Hexadecimal, HEX, consists of numbers from 0
–
9 and letters from A
–
F.
IEEE:
The
I
nstitute of
E
lectrical and
E
lectronics
E
ngineers, which is the largest technical professional
society that promotes the development and application of electrotechnology and allied sciences for the
benefit of humanity, the advancement of the profession. The IEEE fosters the development of
