Area border routers send summary (type 3) advertisements into a stub area or NSSA to describe the routes to other areas. This command is particularly useful to reduce the size of the routing and Link State Database (LSDB) tables within the stub or NSSA.
By default, summary route advertisements are sent into the stub area or NSSA. The no form of the summaries command disables sending summary route advertisements and, in stub areas, the default route is advertised by the area border router.
The following CLI commands are displayed to illustrate route summary features. These command parameters can be defined at the same time stub areas and NSSAs are being configured. See Configuring a stub area and Configuring a not-so-stubby area.
Use the following CLI syntax to configure a route summary:
ospf ospf-instance
area area-id
stub
summaries
nssa
summariesThe following displays a stub route summary configuration example:
A:ALA-49>config>router>ospf# info
----------------------------------------------
asbr
overload
overload-on-boot timeout 60
traffic-engineering
export "OSPF-Export"
exit
area 0.0.0.0
virtual-link 10.0.0.1 transit-area 0.0.0.1
authentication-type message-digest
message-digest-key 2 md5 "Mi6BQAFi3MI" hash
exit
virtual-link 1.2.3.4 transit-area 1.2.3.4
hello-interval 9
dead-interval 40
exit
interface "system"
exit
exit
area 0.0.0.1
exit
area 0.0.0.20
stub
exit
interface "to-103"
exit
exit
area 0.0.0.25
nssa
exit
interface "if2"
priority 100
exit
exit
area 0.0.0.40
interface "test1"
authentication-type password
authentication-key "3WErEDozxyQ" hash
exit
exit
area 1.2.3.4
exit
----------------------------------------------
A:ALA-49>config>router>ospf#
The following displays a stub route summary configuration example:
A:ALA-48>config>router>ospf3# info
----------------------------------------------
asbr
overload
timers
lsa-arrival 50000
exit
export "OSPF-Export"
area 0.0.0.0
virtual-link 4.3.2.1 transit-area 4.3.2.1
exit
interface "system"
exit
exit
area 0.0.0.20
stub
exit
interface "SR1-2"
exit
exit
area 0.0.0.25
nssa
exit
exit
area 4.3.2.1
exit
----------------------------------------------
A:ALA-48>config>router>ospf3#