Juniper IGP - CONFIGURATION GUIDE V11.1.X, Configuration Manual

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area (with the no-summary keyword), or to stop the application of the specified
metric cost, metric type, or a route map to the type 7 default LSAs.
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See area nssa
area stub
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Use to configure a stub area. Stub areas do not get flooded with external LSAs
but do carry a default route, intra-area routes, and interarea routes. The lack of
flooding in stub areas reduces the size of the OSPF database for the area and
decreases memory usage for external routers in the stub area.
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You must configure each router in a stub area as belonging to the stub area.
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You cannot configure virtual links across a stub area.
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Stub areas cannot contain AS boundary routers.
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Use the no-summary keyword to create a “totally stubby area” and restrict type
3 summary LSAs from entering the stub area. However, type 3 default-route
LSAs can continue to flow into the area.
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Example
host1(config-router)# area 47.0.0.0 stub
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Use the no version to disable this function.
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See area stub
area virtual-link
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Use to configure an OSPF virtual link.
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A virtual link is used for areas that do not have a direct connection to the
backbone area.
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To have configured virtual links, the router itself must be an ABR.
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Virtual links are identified by the router ID of the other endpoint, which is also
an ABR.
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The two endpoint routers must be attached to a common area, called the virtual
link’s transit area.
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Virtual links are part of the backbone and behave as if they were unnumbered
point-to-point networks between the two routers.
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A virtual link uses the intra-area routing of its transit area to forward packets.
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Example
host1(config-router)# area 27.0.0.0 virtual-link 27.8.4.2
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Use the no version to remove an OSPF virtual link.
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See area virtual-link
area virtual-link dead-interval
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Configuring OSPF Areas
JUNOSe 11.0.x IP, IPv6, and IGP Configuration Guide