Technical data

contention control
The scheme of access control used by many networks. Control is distributed among
the nodes of the network. Any node wanting to transmit can do so, accessing
the network on a first-come, first-served basis. However, it is possible that two
nodes are in contention, or start transmitting at the same time, in which case a
collision occurs. Each node must then back off and retransmit after waiting a
random period of time.
control cluster
A group of small (256-byte) buffers dynamically allocated from nonpaged pool
memory; stores information related to device sockets, internal control structures,
IP addresses, Internet routes, and Internet packet headers.
Coordinated Universal Time (UTC)
GreenwichMeanTime.
cost
An OSPF (Open Shortest Path First) protocol metric. See metric and OSPF.
counters
The performance and error statistics kept for an entity by network management,
such as lines and nodes.
CRC
See cyclic redundancy check.
cyclic redundancy check (CRC)
An error detection scheme whereby a number is derived from a set of data before it
is transmitted. Once transmitted, the receiving node recalculates the number and
compares it to the value originally transmitted. If the numbers are different, some
type of transmission error has occurred.
daemon
A process that executes in the background waiting for some event to occur.
data cluster
A group of large (1792-byte) buffers that store data in the system space; transmit
and receive operations service user processes by moving data to and from data
clusters.
Data Encryption Key (DEK)
Used for encryption of message text and (with certain choices among a set
of alternative algorithms) for computation of message integrity check (MIC)
quantities.
Data Encryption Standard (DES)
A type of encryption scheme approved by the U.S. National Bureau of Standards.
data link
A logical connection between two systems on the same circuit on which data
integrity is maintained.
Data Link layer
The layer in a network model that handles communication between physical hosts.
data octet
See octet.
data overrun
The data blocks received that arrived too quickly to be processed by the receiver
and were, therefore, lost.
Glossary–11