Cisco ASR 9000 Series Routing Configuration Guide

Understanding hierarchical CLI and CLI inheritance saves you considerable configuration time. See
Configuring Authentication at Different Hierarchical Levels for OSPF Version 2, on page 443 to understand
how to implement these fundamentals. In addition, Cisco IOS XR Software examples are provided in
Configuration Examples for Implementing OSPF , on page 491.
Tip
OSPF Routing Components
Before implementing OSPF, you must know what the routing components are and what purpose they serve.
They consist of the autonomous system, area types, interior routers, ABRs, and ASBRs.
This figure illustrates the routing components in an OSPF network topology.
Figure 17: OSPF Routing Components
Autonomous Systems
The autonomous system is a collection of networks, under the same administrative control, that share routing
information with each other. An autonomous system is also referred to as a routing domain. Figure 17: OSPF
Routing Components, on page 410 shows two autonomous systems: 109 and 65200. An autonomous system
can consist of one or more OSPF areas.
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
410
Implementing OSPF
OSPF Routing Components

Cisco ASR 9000 Series Specifications

General

Brand	Cisco
Model	ASR 9000 Series
Category	Network Router
Language	English