User guide

D-14 Glossary
Switch In networks, a device that filters and forwards packets between
LAN segments. Switches operate at the data link layer (layer 2)
and sometimes the network layer (layer 3) of the OSI Reference
Model and therefore support any packet protocol. LANs that use
switches to join segments are called switched LANs or, in the case
of Ethernet networks, switched Ethernet LANs.
syslog A protocol used for the transmission of event notification
messages across networks, originally developed on the University
of California Berkeley Software Distribution (BSD) TCP/IP system
implementations, and now embedded in many other operating
systems and networked devices. A device generates a messages,
a relay receives and forwards the messages, and a collector (a
syslog server) receives the messages without relaying them.
Syslog uses the user datagram protocol (UDP) as its underlying
transport layer mechanism. The UDP port that has been assigned
to syslog is 514. (RFC3164)
TCP / IP Transmission Control Protocol. TCP, together with IP (Internet
Protocol), is the basic communication language or protocol of the
Internet. Transmission Control Protocol manages the assembling
of a message or file into smaller packets that are transmitted over
the Internet and received by a TCP layer that reassembles the
packets into the original message. Internet Protocol handles the
address part of each packet so that it gets to the right destination.
TCP/IP uses the client/server model of communication in which a
computer user (a client) requests and is provided a service (such
as sending a Web page) by another computer (a server) in the
network.
TFTP Trivial File Transfer Protocol. An Internet software utility for
transferring files that is simpler to use than the File Transfer
Protocol (FTP) but less capable. It is used where user
authentication and directory visibility are not required. TFTP uses
the User Datagram Protocol (UDP) rather than the Transmission
Control Protocol (TCP). TFTP is described formally in Request for
Comments (RFC) 1350.
TKIP Temporal Key Integrity Protocol (TKIP) is an enhancement to the
WEP encryption technique that uses a set of algorithms that
rotates the session keys. TKIPs’ enhanced encryption includes a
per-packet key mixing function, a message integrity check (MIC),
an extended initialization vector (IV) with sequencing rules, and a
re-keying mechanism. The encryption keys are changed (rekeyed)
automatically and authenticated between devices after the rekey
interval (either a specified period of time, or after a specified
number of packets has been transmitted).
TLS Transport Layer Security. (See EAP, Extensible Authentication
Protocol)
ToS / DSCP ToS (Type of Service) / DSCP (Diffserv Codepoint). The ToS/
DSCP box contained in the IP header of a frame is used by
applications to indicate the priority and Quality of Service (QoS)
for each frame. The level of service is determined by a set of
service parameters which provide a three way trade-off between
low-delay, high-reliability, and high-throughput. The use of service
parameters may increase the cost of service.
Term Definition