3Com Switch 8800 Configuration Guide
Chapter 19 OSPF Configuration
19-13
By default, OSPF will not filter the received routing information.
II. Configuring filtering the routes imported to OSPF
Use the
filter-policy export
command to configure the ASBR router to filter the
external routes imported to OSPF. This command is only valid for the ASBR router.
Table 19-10
Enable OSPF to filter the imported routes of other routing protocols
Operation
Command
Enable OSPF to filter the routes
advertised by other routing protocols
filter-policy
{
acl
-
number
|
ip-prefix
ip
-
prefix
-
name
}
export
[
routing
-
process
]
Disable OSPF to filter the advertised
routes by other routing protocols
undo filter-policy
{
acl
-
number
|
ip-prefix
ip
-
prefix
-
name
}
export
[
routing
-
process
]
By default, OSPF does not receive the routes advertised by other routing protocols.
Note:
z
The
filter-policy import
command only filters the OSPF routes of this process
received from the neighbors, and routes that cannot pass the filter will not be added
to the routing table. This command only takes effect on ABR.
z
The
filter-policy export
command only takes effect on the routes imported by the
import-route
command. If you configure the switch with only the
filter-policy
export
command, but without configuring the
import-route
command to import
other external routes (including OSPF routes of different process), then the
filter-policy export
command does not take effect.
z
If the
filter-policy export
command does not specify which type of route is to be
filtered, it takes effect on all routes imported by the local device using the
import-route
command.
19.2.8 Configuring the Route Summary of OSPF
I. Configuring the route summary of OSPF area
Route summary means that ABR can aggregate information of the routes of the same
prefix and advertise only one route to other areas. An area can be configured with
multiple aggregate segments, thereby OSPF can summarize them. When the ABR
transmits routing information to other areas, it will generate Sum_net_Lsa (type-3 LSA)
per network. If some continuous networks exist in this area, you can use the
abr-summary
command to summarize these segments into one segment. Thus, the
ABR only needs to send an aggregated LSA, and all the LSAs in the range of the