Cisco IPS-4255-K9 Installation Guide - Page 379

Glossary DRAM DTE DTP dynamic random-access memory. RAM that stores information in capacitors that must be refreshed periodically. Delays can occur because DRAMs are inaccessible to the processor when refreshing their contents. However, DRAMs are less complex and have greater capacity than SRAMs. Data Terminal Equipment. Refers to the role of a device on an RS-232C connection. A DTE writes data to the transmit line and reads data from the receive line. Dynamic Trunking Protocol. A Cisco proprietary protocol in the VLAN group used for negotiating trunking on a link between two devices and for negotiating the type of trunking encapsulation (ISL or 802.1q) to be used. E ECLB Ether Channel Load Balancing. Lets a Catalyst switch split traffic flows over different physical paths. egress Traffic leaving the network. encryption Application of a specific algorithm to data to alter the appearance of the data making it incomprehensible to those who are not authorized to see the information. engine A component of the sensor designed to support many signatures in a certain category. Each engine has parameters that can be used to create signatures or tune existing signatures. enterprise network Large and diverse network connecting most major points in a company or other organization. Differs from a WAN in that it is privately owned and maintained. escaped expression Used in regular expression. A character can be represented as its hexadecimal value, for example, \x61 equals 'a,' so \x61 is an escaped expression representing the character 'a.' ESD electrostatic discharge. Electrostatic discharge is the rapid movement of a charge from one object to another object, which produces several thousand volts of electrical charge that can cause severe damage to electronic components or entire circuit card assemblies. event An IPS message that contains an alert, a block request, a status message, or an error message. Event Store One of the components of the IPS. A fixed-size, indexed store used to store IPS events. evIdsAlert The XML entity written to the Event Store that represents an alert. F fail closed fail open false negative false positive Blocks traffic on the device after a hardware failure. Lets traffic pass through the device after a hardware failure. A signature is not fired when offending traffic is detected. Normal traffic or a benign action causes a signature to fire. OL-18504-01 Cisco Intrusion Prevention System Appliance and Module Installation Guide for IPS 7.0 GL-7