MCSA/MCSE Self-Paced Training Kit (Exam 70-270): Installing ...

Glossary G-29
Open Systems Interconnection (OSI) reference model A seven-layer architecture
that standardizes levels of service and types of interaction for computers
exchanging information through a network. It is used to describe the flow of data
between the physical connection to the network and the end user application.
This model is the best-known and most widely used model for describing networking
environments.
organizational unit (OU) A container used to organize objects within a domain into
logical administrative groups. An OU can contain objects such as user accounts,
groups, computers, printers, applications, file shares, and other OUs.
OSI See Open Systems Interconnection (OSI) reference model.
OU See organizational unit (OU).
Owner The user who created a file, folder, or printer.
P
packet A unit of information transmitted as a whole from one device to another on
a network. In packet-switching networks, a packet is defined more specifically as
a transmission unit of fixed maximum size that consists of binary digits representing
data; a header containing an identification number, a source, and destination
addresses; and sometimes error-control data. See also frame.
Packet Internet Groper (ping) A simple tool that tests if a network connection is
complete, from the server to the workstation, by sending a message to the remote
computer. If the remote computer receives the message, it responds with a reply
message. The reply consists of the remote workstation’s Internet Protocol (IP)
address, the number of bytes in the message, how long it took to reply—given in
milliseconds (ms)—and the length of Time to Live (TTL) in seconds. Ping works at
the IP level and often responds even when higher level TCP-based services cannot
respond.
packet switching A message delivery technique in which small units of information
(packets) are relayed through stations in a computer network along the best route
available between the source and the destination. Data is broken into smaller units
and then repacked in a process called packet assembly/disassembly (PAD).
Although each packet can travel along a different path, and the packets composing
a message can arrive at different times or out of sequence, the receiving computer
reassembles the original message. Packet-switching networks are considered
fast and efficient. Standards for packet switching on networks are documented in
the CCITT recommendation X.25.