iTP Secure WebServer System Administrator's Guide (Version 7.0)

Glossary
iTP Secure WebServer System Administrator’s Guide—523346-012
Glossary-3
Internet Protocol (IP)
Internet Protocol (IP). The Internet standard protocol that defines the Internet datagram as
the unit of information passed across the Internet and that provides the basis for the
Internet connectionless, best-effort packet delivery service.
Internet. Physically, a collection of packet-switching networks interconnected by gateways,
along with protocols that allow them to function logically as a single, large, virtual
network. When written in uppercase, INTERNET refers specifically to the DARPA
Internet and the TCP/IP protocols it uses.
interoperability. The ability of software and hardware on multiple machines from multiple
vendors to communicate meaningfully.
IP. See Internet Protocol (IP).
ITU-T. A division of the United Nations International Telecommunications Union that
coordinates standards-setting activities.
Joint Photographic Expert Group (JPEG). An image format used to transmit graphics on
the World Wide Web (WWW).
JPEG. See Joint Photographic Expert Group (JPEG).
key database file. The file in which you maintain keys you generated using the keyadmin
command with either the -mkpair or -keydb argument. These are the keys you use to
generate certificates for software encryption.
Key Exchange Key (KEK). An encryption key used to encrypt other keys.
local area network (LAN). Any physical network technology that operates at high speed
(usually from tens of megabits per second to several gigabits per second) over short
distances (up to a few thousand meters).
Mosaic. See browser.
Nagle’s Algorithm. Nagle's algorithm is a means of improving the efficiency of TCP/IP
networks by reducing the number of packets that need to be sent over the network.
This algorithm provides a relief for 'small-packet' problem by controlling the congestion
in TCP/IP. The 'small packet' problem arises when an application repeatedly emits data
in small chunks, frequently only 1 byte in size. Since TCP packets have a 40 byte
header (20 bytes for TCP, 20 bytes for IPv4), this results in a 41 byte packet for 1 byte
of useful information, a huge overhead. The situation becomes worse, over slow links,
where many such packets can be in transit at the same time, potentially leading to
congestion collapse.
Nagle's algorithm works by coalescing a number of small outgoing messages, and
sending them all at once. Specifically, as long as there is a sent packet for which the
sender has received no acknowledgment, the sender should keep buffering its output
until it has a full packet's worth of output, so that output can be sent all at once.