Brocade TurboIron 24X Series Configuration Guide - Manual (Page 652)

618 Brocade TurboIron 24X Series Configuration Guide
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Configuring OSPF
The no-summary parameter applies only to stub areas and disables summary LSAs from being sent
into the area.
NOTE
You can assign one area on a router interface. For example, if the system or chassis module has 16
ports, 16 areas are supported on the chassis or module.
Assign a Not-So-Stubby Area (NSSA)
The OSPF Not So Stubby Area (NSSA) feature enables you to configure OSPF areas that provide the
benefits of stub areas, but that also are capable of importing external route information. OSPF
does not flood external routes from other areas into an NSSA, but does translate and flood route
information from the NSSA into other areas such as the backbone.
NSSAs are especially useful when you want to summarize Type-5 External LSAs (external routes)
before forwarding them into an OSPF area. The OSPF specification (RFC 2328) prohibits
summarization of Type-5 LSAs and requires OSPF to flood Type-5 LSAs throughout a routing
domain. When you configure an NSSA, you can specify an address range for aggregating the
external routes that the NSSA's ABR exports into other areas.
The Brocade implementation of NSSA is based on RFC 1587.
Figure 98 shows an example of an OSPF network containing an NSSA.
FIGURE 98 OSPF network containing an NSSA