Hirschmann HiSecOS EAGLE30 - OSPF Not so Stubby Areas

Routing > OSPF > NSSA
Routing
RM GUI HiSecOS EAGLE20/30
Release 3.0 09/2015
315
Routing > OSPF > NSSA
8.13 OSPF Not So Stubby Areas
NSSAs are similar to the OSPF stub area, but have the additional capability
of importing limited AS external routes. The ABR sends external routes out
of the NSSA by converting type 7 AS external LSAs into type 5 AS external
LSAs. The ASBR in a NSSA originates type 7 LSAs. The only difference
between the type 5 and type 7 LSAs is that the router sets the “N“ bit for
NSSAs. Both NSSA neighbors have the "N" bit set so that the OSPF
neighbor adjacency forms.
Beside the internal data traffic, NSSAs act like transit areas by transport data
coming from external sources to other areas within the OSPF domain.
The device allows you to create an NSSA or change an existing area to an
NSSA.
 To create an NSSA, first create an entry in the "OSPF Areas" table, then
change "Area Type" to
NSSA .
 For an existing area, simply change the "Area Type" to
NSSA .
 Table
Parameters Meaning
Area ID Displays the area ID to which the table entries apply.
Possible values:
 Range area IDs
Redistribute Activates/deactivates external route redistribution into the NSSA.
Possible values:
 marked (default setting)
When set to active, the NSSA ASBRs suppress external route
redistribution into the NSSA. Furthermore, the ASBR ceases to create
type 7 external LSAs for external routes.
 unmarked
The NSSA ASBRs redistribute external routes into the NSSA.