Configuring route summarization when redistributing routes into OSPF on an ASBR
Without route summarization, an ASBR advertises each redistributed route in a separate ASE LSA. After
a summary route is configured, the ASBR advertises only the summary route in an ASE LSA instead of
more specific routes, which reduces the number of LSAs in the LSDB.
The ASBR summarizes redistributed Type-5 LSAs that fall into the specified address range. If the ASBR is
in an NSSA area, it also summarizes Type-7 LSAs that fall into the specified address range. If the ASBR
is also the ABR, it summarizes Type-5 LSAs translated from Type-7 LSAs.
Follow these steps to configure route summarization when redistributing routes into OSPF on an ASBR:
To do...
Enter system view
Enter OSPF view
Configure ASBR route
summarization
Configuring OSPF inbound route filtering
NOTE:
For more information about IP prefix list and routing policy, see the chapter "Routing policy
configuration."
OSPF calculates routes by using LSAs. The calculated routes can be filtered and only permitted routes are
installed into the OSPF routing table.
OSPF provides the following filtering methods:
Filters routing information by destination address through ACLs and IP address prefixes
•
Filters routing information by next hop through the filtering criteria configured with the gateway
•
keyword
•
Filters routing information by destination address through ACLs and IP address prefixes and by next
hop through the filtering criteria configured with the gateway keyword
Filters routing information by routing policy specified by the route-policy keyword
•
Follow these steps to configure inbound route filtering:
To do...
Enter system view
Enter OSPF view
Configure inbound route
filtering
Use the command...
system-view
ospf [ process-id | router-id router-id
| vpn-instance vpn-instance-name ]*
asbr-summary ip-address { mask |
mask-length } [ tag tag | not-advertise
| cost cost ] *
Use the command...
system-view
ospf [ process-id | router-id router-id |
vpn-instance vpn-instance-name ] *
filter-policy { acl-number [ gateway
ip-prefix-name ] | gateway ip-prefix-name |
ip-prefix ip-prefix-name [ gateway
ip-prefix-name ] | route-policy
route-policy-name } import
81
Remarks
—
—
Required
The command is available on an
ASBR only.
Not configured by default.
Remarks
—
—
Required
Not configured by default.