Technical data

primary server
A BIND name server that maintains the database for a zone; secondary servers
copy their information from primary servers. Also called primary master or master
server. See also BIND server, cache server, forwarder server,andsecondary
server.
printcap database
The Compaq TCP/IP Services for OpenVMS database that maps local queues to
printers on remote hosts; specifies local queues for LPD printing from remote
hosts. Equivalent to the UNIX
/etc/printcap
file.
privileged port
A port in which the remote host has done some level of checking against the
application using the port; privileged port numbers range from 1 to 1023.
process
The context within a system in which a specific computing session occurs; provides
the context in which an application executes.
protocol
A set of rules that controls the communications between computers. Also, a set of
conventions between communicating processes regarding the format and contents
ofmessagestobeexchanged.
Protocols can describe low-level details of machine-to-machine interfaces, such
as the order in which the bits from a byte are set across a wire, or high-level
exchanges between applications programs such as the way in which two programs
transfer a file across the Internet.
protocol data unit (PDU)
The unit of data sent across a network. Also called a packet.
protocol machine
The set of data structures and routines that implements a specific protocol and
controls the progress of a communication between peer entities.
protocol overhead
The part of communications data or processing not directly consumed by the users
but necessary to successfully bring about the transfer of user information.
protocol port
An abstraction that transport protocols use to distinguish among multiple
destinations within a given host computer. Internet protocols identify ports using
small positive integers. Usually the operating system allows an application
program to specify which port it wants to use. Some ports are reserved for standard
services such as electronic mail.
protocol transparency
The quality in a communications device or system that allows various higher-level
protocols to coexist on the same wire. The protocols are transparent to the device
or system.
The degree to which users of underlying protocols are aware of the specifics of
those protocols.
protocol sequence
An ordered list of protocol identifiers.
Glossary–35