Cisco Systems Cisco IOS XR manual GL-10

Glossary

routing metric

routing protocol

routing table

RP

RPF

RSVP

running configuration

Rx

A routing algorithm determines that one route is better than another. This information is stored in routing tables. Metrics include bandwidth, communication cost, delay, hop count, load, MTU, path cost, and reliability. Sometimes referred to simply as a metric. See also algorithm.

Protocol that accomplishes routing through the implementation of a specific routing algorithm. Examples of routing protocols include BGP, OSPF, and IS-IS.

Table stored in a router or some other internetworking device that keeps track of routes to particular network destinations and, in some cases, metrics associated with those routes.

route processor. Cards that contain run-control software on the router. Two RPs are installed as a redundant pair in dedicated slots in the front of each line card chassis.

Reverse Path Forwarding. Multicasting technique in which a multicast datagram is forwarded from all but the receiving interface if the receiving interface is the one used to forward unicast datagrams to the source of the multicast datagram.

Resource Reservation Protocol. Protocol that supports the reservation of resources across an IP network. Applications running on IP end systems can use RSVP to indicate to other nodes the nature (bandwidth, jitter, maximum burst, and so on) of the packet streams they want to receive. RSVP depends on IPv6. Also known as Resource Reservation Setup Protocol. See also IPv6.

The router configuration currently in effect. Although the user can save multiple versions of the router configuration for future reference, only one copy of the running configuration exists in the router at any given time.

The receiver end of a fabric link. All links are unidirectional. See also Tx.

S

SCFC			shelf controller/fan controller. Combines shelf controller function and fan controller function on one
			card. Two are installed in each fabric chassis.
SDH			Synchronous Digital Hierarchy. European standard that defines a set of rate and format standards that
			are sent using optical signals over fiber. SDH is similar to SONET, with a basic SDH rate of
			155.52 Mbps, designated at STM-1.
SDR			secure domain router. A collection of line cards and route processors that form a complete router. Each
			router contains its own instance of dynamic routing, IP stack, system database, interface manager, and
			event notification system.
SDRAM			synchronous dynamic random access memory. A form of dynamic RAM that adds a separate clock
			signal to the control signals.
shelf controller			The hardware component that manages the configuration and health of a fabric chassis within the
			Cisco CRS-1 router.
shelf manager			The shelf manager process runs on a router or switch, doing platform-dependent functions, including
			handling OIR events. Shelf manager is formerly called platform manager.
SMU			Software Maintenance Upgrade. A “point fix” for a critical problem. SMUs are delivered as PIE files
			and are used to update software packages.
		Cisco IOS XR Getting Started Guide
	GL-10		OL-10957-02