
Customizing OSPF Services
114065 Rev. A 5-35
Assume, for example, that the stub area in Figure 5-1 has been configured to
import no internal or external routing information. Border router 8 receives ASEs
and internal summaries from its interface to the backbone. However, Border
router 8 does not forward the ASEs or summaries to the stub. Instead, it injects a
default route that internal routers use to forward datagrams to destinations beyond
the stub.
By default, a border router imports ASEs into its attached areas. You can use Site
Manager to disable and re-enable the importing of ASEs for a stub area.
By default, a border router that injects a default route into a stub area assigns a
cost metric of 1 to that default route. You can use Site Manager to specify a cost
metric (overriding the default).
By default, a border router injects network summaries into an attached stub area.
You can use Site Manager to disable the injection of summaries.
Applying IP Policies to OSPF Interfaces
According to the OSPF standard, all routers in a given area must maintain a
similar routing database. To ensure the integrity of the database, the network
administrator must not use IP policies to manipulate link-state advertisements
before propagating them on an interface.
There are two ways, however, in which an IP policy can be applied to an OSPF
interface:
• An OSPF announce policy can be used on a boundary router to control which
self-originated external routing updates are placed in the link-state database
for distribution according to the OSPF standard. The announce policy affects
what other routers learn but only with regard to the local boundary router’s
self-originated information.
Site Manager: Import AS Extern parameter: page A-86
Site Manager: Stub Metric parameter: page A-87
Site Manager: Import Summaries parameter: page A-87
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