configure ospf area nssa stub-default-cost

configure ospf area area-identifier nssa [summary | nosummary] stub-default-cost cost {translate}

Description

Configures an OSPF (Open Shortest Path First) area as an NSSA.

Syntax Description

`area-identifier`	Specifies an OSPF area.
summary	Specifies that type-3 can be propagated into the area.
nosummary	Specifies that type-3 cannot be propagated into the area.
`cost`	Specifies a cost metric.
translate	Specifies whether type-7 LSAs are translated into type-5 LSAs.

Default

N/A.

Usage Guidelines

NSSAs are similar to the existing OSPF stub area configuration option, but have the following two additional capabilities:

External routes originating from an ASBR connected to the NSSA can be advertised within the NSSA.
External routes originating from the NSSA can be propagated to other areas, including the backbone area, if translated to type 5 LSAs.

When configuring an OSPF area as an NSSA, the translate option should only be used on NSSA border routers, where translation is to be enforced. If translate is not used on any NSSA border router in a NSSA, one of the ABRs for that NSSA is elected to perform translation (as indicated in the NSSA specification). The option should not be used on NSSA internal routers. Doing so inhibits correct operation of the election algorithm.

Example

The following command configures an OSPF area as an NSSA:

configure ospf area 10.1.1.0 nssa summary stub-default-cost 10 translate

History

This command was first available in ExtremeXOS 10.1.

Platform Availability

This command is available on platforms with an Advanced Edge or Core license as described in the ExtremeXOS 22.2 Feature License Requirements document.

Published August 2017prev | next

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