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Cisco Content Services Switch Routing and Bridging Configuration Guide
OL-8241-02
Chapter3 Configuring Open Shortest Path First
OSPF Overview
OSPF Routing Hierarchy

The OSPF routing hierarchy includes the following functions:

•Autonomous systems
•Areas, including the backbone and stub areas
•Area Border Routers (ABRs)
•Autonomous System Boundary Routers (ASBRs)

Figure 3-1 illustrates an OSPF network topology.

Figure3-1 Basic OSPF Network Topology
Router3 Router5
AS
Boundry
Router2
Router1
(CSS)
Router4
Router2
AS
Boundry
Router1
Area
Border
Router1
Area
Border
Router2
Autonomous System A (AS A) Autonomous System B (AS B)
Area 1.1.1.1
Area 0.0.0.0 (backbone)
Area 1.1.1.2
(stub area)
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