Wireless Access Point
Glossary of Terms 613
MTU
(Maximum Transmission Unit) The largest physical packet size — measured in
bytes — that a network can transmit. Any messages larger than the MTU are
divided into smaller packets before being sent. Every network has a different
MTU, which is set by the network administrator. Ideally, you want the MTU to be
the same as the smallest MTU of all the networks between your machine and
a message's final destination. Otherwise, if your messages are larger than one of
the intervening MTUs, they will get broken up (fragmented), which slows down
transmission speeds.
NTP
(Network Time Protocol) An Internet standard protocol (built on top of TCP/IP)
that ensures the accurate synchronization (to the millisecond) of computer clock
times in a network of computers. Running as a continuous background client
program on a computer, NTP sends periodic time requests to servers, obtaining
server time stamps and using them to adjust the client's clock.
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.
POE
This refers to the optional Xirrus-supplied Power over Gigabit Ethernet modules
that provide DC power to APs. 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.