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BLADEOS 6.5.2 Application Guide
BMD00220, October 2010 Chapter 20: OSPF 275
Types of OSPF Routing Devices
As shown in Figure 31, OSPF uses the following types of routing devices:
Internal Router (IR)—a router that has all of its interfaces within the same area. IRs maintain
LSDBs identical to those of other routing devices within the local area.
Area Border Router (ABR)—a router that has interfaces in multiple areas. ABRs maintain one
LSDB for each connected area and disseminate routing information between areas.
Autonomous System Boundary Router (ASBR)—a router that acts as a gateway between the
OSPF domain and non-OSPF domains, such as RIP, BGP, and static routes.
Figure 31 OSPF Domain and an Autonomous System
Backbone
Area 0
Area 3
Area 2
Area 1
Inter-Area Routes
(Summary Routes)
ABR
ABR
ABR
ASBR
Internal
Router
ASBR
External
Routes
BGP
RIP
OSPF Autonomous System