Glossary
GL-5
Cisco IOS XR Getting Started Guide
OL-10957-02
I
ICMP Internet Control Message Protocol. Network layer Internet (TCP/IP) protocol that reports errors and
provides other information relevant to IP packet processing.
IEP IP explicit path. List of IP addresses, each representing a node or link in the explicit path.
IETF Internet Engineer ing Task Force. Task force consisting of over 80 working groups responsible for
developing Internet standards. The IETF operates under the auspices of ISOC.
IGMP Internet Group Management Protocol. Governs the management of multicast groups in a TCP/IP
network. Used by IP hosts to report their multicast group memberships to an adjacent multicast router.
IGP Interior Gateway Protocol. Internet protocol used to exchange routing information within an
autonomous system. Examples of common Internet IGPs include IGRP, OSPF, and RIP. See also OSPF
and RIP.
ingress Incoming channel.
installed software
set
The set of CiscoIOS XR software packages installed on a router.
IOSXR The Cisco operating system used on the Cisco CRS-1 rout er and Cisco XR 12000 Series Router.
IP Internet Protocol. Network layer protocol in the TCP/IP stack offering a connectionless internetwork
service. IP provides features for addressing, type-of-serv ice specification, fragmentation and
reassembly, and security.
IPv4 IP Version 4. Network layer for the TCP/IP protocol suite. A connectionless, best-effort packet
switching protocol.
IPv6 IP Version 6. Replacement for IPv4. A next-generation IP protocol. IPv6 is backward compati ble with
and designed to fix the shortcomings of IPv4, such as data se curity and maximum number of user
addresses. IPv6 increases the address space from 32 to 128 bits, providing f or an unlimited number of
networks and systems. It also supports quality of service (QoS) pa rameters for real-time audio and
video.
IPX Internetwork Packet Exchange. NetWare network layer (Layer 3) protocol used for t ransferring data
from servers to workstations. IPX is similar to IP and XNS.
IS-IS Intermediate System-to-Intermediate System. OSI link-state hierarchical routing protocol based on
DECnet Phase V routing, whereby ISs (routers) exchange routing information based on a single metric
to determine network topology.
K
keepalive interval Period of time between each keepalive message sent by a network device.
keepalive message Message sent by one network device to inform another network device that the virtual circuit betwee n
the two is still active.