CCNA Cisco Certified Network Associate Study Guide - FTP Server

714 Glossary
TRIP Token Ring Interface Processor: A high-speed interface processor
used on Cisco 7000 series routers. The TRIP provides two or four ports for
interconnection with IEEE 802.5 and IBM media with ports set to speeds of
either 4Mbps or 16Mbps set independently of each other.
trunk link Link used between switches and from some servers to the
switches. Trunk links carry information about many VLANs. Access links
are used to connect host devices to a switch and carry only VLAN information
that the device is a member of.
TTL Time To Live: A field in an IP header, indicating the length of time a
packet is valid.
TUD Trunk Up-Down: A protocol used in ATM networks for the monitoring
of trunks. Should a trunk miss a given number of test messages being
sent by ATM switches to ensure trunk line quality, TUD declares the trunk
down. When a trunk reverses direction and comes back up, TUD recognizes
that the trunk is up and returns the trunk to service.
tunneling A method of avoiding protocol restrictions by wrapping
packets from one protocol in another protocol’s packet and transmitting this
encapsulated packet over a network that supports the wrapper protocol. See
also: encapsulation.
U reference point Reference point between a TE1 and an ISDN network.
The U reference point understands ISDN signaling techniques and uses a 2wire
connection.
UDP User Datagram Protocol: A connectionless Transport layer protocol
in the TCP/IP protocol stack that simply allows datagrams to be exchanged
without acknowledgements or delivery guarantees, requiring other protocols
to handle error processing and retransmission. UDP is defined in
RFC 768.
unnumbered frames HDLC frames used for control-management purposes,
such as link startup and shutdown or mode specification.
UTP unshielded twisted-pair: Copper wiring used in small-to-large networks
to connect host devices to hubs and switches. Also used to connect
switch to switch or hub to hub.