User's Manual

Wireless Array
Glossary of Terms 499
packet
Data sent over a network is broken down into many small pieces — packets — by
the Transmission Control Protocol layer of TCP/IP. Each packet contains the
address of its destination as well the data. Packets may be sent on any number of
routes to their destination, where they are reassembled into the original data. This
system is optimal for connectionless networks, such as the Internet, where there
are no fixed connections between two locations.
PLCP
(Physical Layer Convergence Protocol) Defined by IEEE 802.6, a protocol
specified within the Transmission Convergence layer that defines exactly how
cells are formatted within a data stream for a particular type of transmission
facility.
PoGE
This refers to the optional Xirrus-supplied Power over Gigabit Ethernet modules
that provide DC power to Arrays. Power is supplied over the same Cat 5e or Cat 6
cable that supplies the data connection to your gigabit Ethernet switch, thus
eliminating the need to run a power cable.
preamble
Preamble (sometimes called a header) is a section of data at the head of a packet
that contains information that the access point and client devices need when
sending and receiving packets. PLCP Has two structures, a long and a short
preamble. All compliant 802.11b systems have to support the long preamble.
The short preamble option is provided in the standard to improve the efficiency
of a network's throughput when transmitting special data, such as voice, VoIP
(Voice-over IP) and streaming video.
private key
In cryptography, one of a pair of keys (one public and one private) that are created
with the same algorithm for encrypting and decrypting messages and digital
signatures. The private key is provided only to the requestor and never shared.
The requestor uses the private key to decrypt text that has been encrypted with
the public key by someone else.
PSK
(Pre-Shared Key) A TKIP passphrase used to protect your network traffic in WPA.