Troubleshooting OSPF
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F I G U R E 6 . 1 2
OSPF peer initialization
OSPF Area Types
OSPF uses areas in place of an autonomous system. An OSPF area consists of
a group of routers or interfaces on a router that is assigned to a common area.
OSPF also allows and uses different area types. When deploying OSPF,
there must be a backbone area. Standard and stub areas connect to the back-
bone area. Below is a list of each router type, followed by a short description
of the area type.
Backbone This area accepts all LSAs and is used to connect multiple
areas.
Stub This area does not accept any external routing update, but it
accepts summary LSAs.
Totally Stub These areas are closed off from accepting external or sum-
mary advertisements.
Standard This is the normal area that accepts internal and external
LSAs, and summary information.
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