Technical data

gateway
A communications device or program that passes data between networks having
similar functions but dissimilar implementations. The term router is now used in
place of the original definition of gateway.
An intermediate destination by which packets are delivered to their ultimate
destination.
A host address of another router that is directly reachable through an attached
network. As with any host address it may be specified symbolically.
gateway client
Another term for an access system.
Gateway Routing Daemon
See GATED.
GID
See group identification.
gigabit
One billion bits.
gigabyte
One billion bytes.
group identification (GID)
The identification code for a group of UNIX users.
half-duplex circuit
A circuit designed for transmission in either direction, but only one direction at one
time. Contrast with full-duplex circuit.
half-duplex transmission
Data transmission in either direction, but only one direction at a time. Contrast
with full-duplex transmission.
handshaking sequence
The exchange of connection information between two communicating entities;
takes place to enable the successful completion of a connection. Used, for example,
in establishing a TCP connection between client and server applications.
hardware address
The address that identifies the connection device between the network controller
of a host and the network cable. See also address.
hard link
A mechanism that allows you to assign more than one name to a file. Both the new
name and the file being linked must be in the same file system. See also link.
header
The portion of a packet that precedes the actual data and contains control
information such as source and destination address and error checking.
header compression
A technique used by PPP and SLIP protocols to reduce the number of bytes per
frame when sending packets over a slow serial link. The use of header compression
is negotiated between the client and servers processes to reduce the size of the IP
and TCP headers.
Glossary–19