HP 3500YL - Manual (Page 229)

IP Routing Features
Configuring OSPF
Replacing Type-3 Summary LSAs and Type-7 Default External
LSAs with a Type-3 Default Route LSA
By default, a routing switch operating as an ABR for a stub area or NSSA injects
non-default, summary routes (LSA type 3) into the stub areas and NSSAs. For
NSSAs, the routing switch also injects a type-7 default external route. You can
further reduce LSA traffic into these areas by using
no-summary. This command
option configures the routing switch to:
■ Replace type-3 summary LSA injection into a stub area or NSSA with a
type-3 default summary route (0.0.0.0/0).
■ Disable injection of the type-7 default external route into an NSSA.
You can enable this behavior when you first configure the stub area or NSSA,
or at a later time. (For the full command to use, refer to “Configuring a Stub
or NSSA Area” on page 5-67.)
The no-summary command does not affect intra-area advertisements, meaning
the switch still accepts summary LSAs from OSPF neighbors within its area
and floods them to other neighbors. The switch can form adjacencies with
other routers regardless of whether summarization is enabled or disabled for
areas on each switch.
When you use no-summary, the change takes effect immediately. If you apply
the option to a previously configured area, the switch flushes all of the
summary LSAs it has generated (as an ABR) from the area.
N o t e This feature applies only when the switch is configured as an Area Border
Router (ABR) for a stub area or NSSA. To completely prevent summary LSAs
from injection into the area, use
no-summary to disable the summary LSAs on
each OSPF router that is an ABR for the area.
To implement the above operation for a stub area or NSSA, enter a command
such as the following:
ProCurve(ospf)# area 40 stub 3 no-summary
5-55