Glossary
GL-23
Cisco Intrusion Prevention System Sensor CLI Configuration Guide for IPS 7.2
OL-29168-01
trusted certificate
Certificate upon which a certificate user relies as being valid without the need for validation testing;
especially a public-key certificate that is used to provide the first public key in a certification path.
trusted key
Public key upon which a user relies; especially a public key that can be used as the first public key in
a certification path.
tune
Adjusting signature parameters to modify an existing signature.
U
UDI
Unique Device Identifier. Provides a unique identity for every Cisco product. The UDI is composed of
the PID, VID, and SN. The UDI is stored in the Cisco IPS ID PROM.
UDLD
UniDirectional Link Detection. Cisco proprietary protocol that allows devices connected through
fiber-optic or copper Ethernet cables connected to LAN ports to monitor the physical configuration of
the cables and detect when a unidirectional link exists. When a unidirectional link is detected, UDLD
shuts down the affected LAN port and sends an alert, since unidirectional links can cause a variety of
problems, such as, spanning tree topology loops.
UDP
User Datagram Protocol. Connectionless transport layer protocol in the TCP/IP protocol stack. UDP is
a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery,
requiring that error processing and retransmission be handled by other p rotocols. UDP is defined in
RFC 768.
unblock
To direct a router to remove a previously applied block.
UniDirectional Link
Detection
See UDLD.
unvirtualized
sensing interface
An unvirtualized sensing interface has not been divided into subinterfaces and the entire interfaces can
be associated with at most one virtual sensor.
UPS
Uninterruptable Power Source.
UTC
Coordinated Universal Time. Time zone at zero degrees longitude. Formerly called Greenwich Mean
Time (GMT) and Zulu time.
UTF-8
8-bit Unicode Transformation Format. A variable-length character encoding for Unicode. UTF-8 can
represent every character in the Unicode character set and is backwards-compatible with ASCII.
V
VACL
VLAN ACL. An ACL that filters all packets (both within a VLAN and between VLANs) that pass
through a switch. Also known as security ACLs.
VID
Version identifier. Part of the UDI.
VIP
Versatile Interface Processor. Interface card used in Cisco 7000 and Cisco 7500 series routers. The VIP
provides multilayer switching and runs Cisco IOS. The most recent version of the VIP is VIP2.