Cisco IPS-4255-K9 - Intrusion Protection Sys 4255 Installation Manual page 394

Glossary
Message sent by an SNMP agent to an NMS, a console, or a terminal to indicate the occurrence of a
trap
significant event, such as a specifically defined condition or a threshold that was reached.
Analyzes traffic from nonstandard protocols, such as BO2K and TFN2K.
Trojan engine
Physical and logical connection between two switches across which network traffic travels. A backbone
trunk
is composed of a number of trunks.
Certificate upon which a certificate user relies as being valid without the need for validation testing;
trusted certificate
especially a public-key certificate that is used to provide the first public key in a certification path.
Public key upon which a user relies; especially a public key that can be used as the first public key in
trusted key
a certification path.
Adjusting signature parameters to modify an existing signature.
tune
U
Unique Device Identifier. Provides a unique identity for every Cisco product. The UDI is composed of
UDI
the PID, VID, and SN. The UDI is stored in the Cisco IPS ID PROM.
UniDirectional Link Detection. Cisco proprietary protocol that allows devices connected through
UDLD
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.
User Datagram Protocol. Connectionless transport layer protocol in the TCP/IP protocol stack. UDP is
UDP
a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery,
requiring that error processing and retransmission be handled by other protocols. UDP is defined in
RFC 768.
To direct a router to remove a previously applied block.
unblock
See UDLD.
UniDirectional Link
Detection
An unvirtualized sensing interface has not been divided into subinterfaces and the entire interfaces can
unvirtualized
be associated with at most one virtual sensor.
sensing interface
Uninterruptable Power Source.
UPS
Coordinated Universal Time. Time zone at zero degrees longitude. Formerly called Greenwich Mean
UTC
Time (GMT) and Zulu time.
V
VLAN ACL. An ACL that filters all packets (both within a VLAN and between VLANs) that pass
VACL
through a switch. Also known as security ACLs.
Cisco Intrusion Prevention System Appliance and Module Installation Guide for IPS 7.0
GL-22
OL-18504-01