Cisco IPS-4255-K9 Installation Guide - Page 381

Glossary global correlation database GMT GRUB The collective information obtained from and shared with collaborative devices such as IPS sensors. Greenwich Mean Time. Time zone at zero degrees longitude. Now called Coordinated Universal Time (UTC). Grand Unified Bootloader. Boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to the operating system kernel software. The kernel, in turn, initializes the rest of the operating system. H H.225.0 H.245 H.323 half duplex handshake hardware bypass host block HTTP HTTPS An ITU standard that governs H.225.0 session establishment and packetization. H.225.0 actually describes several different protocols: RAS, use of Q.931, and use of RTP. An ITU standard that governs H.245 endpoint control. Allows dissimilar communication devices to communicate with each other by using a standardized communication protocol. H.323 defines a common set of CODECs, call setup and negotiating procedures, and basic data transport methods. Capability for data transmission in only one direction at a time between a sending station and a receiving station. BSC is an example of a half-duplex protocol. Sequence of messages exchanged between two or more network devices to ensure transmission synchronization. A specialized interface card that pairs physical interfaces so that when a software error is detected, a bypass mechanism is engaged that directly connects the physical interfaces and allows traffic to flow through the pair. Hardware bypass passes traffic at the network interface, does not pass it to the IPS system. ARC blocks all traffic from a given IP address. Hypertext Transfer Protocol. The stateless request/response media transfer protocol used in the IPS architecture for remote data exchange. An extension to the standard HTTP protocol that provides confidentiality by encrypting the traffic from the website. By default this protocol uses TCP port 443. I ICMP ICMP flood Internet Control Message Protocol. Network layer Internet protocol that reports errors and provides other information relevant to IP packet processing. Documented in RFC 792. Denial of Service attack that sends a host more ICMP echo request ("ping") packets than the protocol implementation can handle. OL-18504-01 Cisco Intrusion Prevention System Appliance and Module Installation Guide for IPS 7.0 GL-9