HP VPN Firewall Appliances Network Management Configuration Guide
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Configuring IS-IS route filtering
You can use an ACL, IP prefix list, or routing policy to filter routes calculated using the received LSPs and
routes redistributed from other routing protocols.
Filtering routes calculated from received LSPs
IS-IS saves LSPs received from neighbors in the LSDB, uses the SPF algorithm to calculate the shortest path
tree with itself as the root, and installs the routes into the IS-IS routing table.
Perform this task to filter calculated routes. Only routes not filtered can be added into the IS-IS routing
table.
To filter routes calculated using received LSPs:
Ste
p
Command
Remarks
1. Enter system view.
system-view N/A
2. Enter IS-IS view.
isis [ process-id ] [ vpn-instance
vpn-instance-name ]
N/A
3. Filter routes calculated
from received LSPs.
filter-policy { acl-number | ip-prefix
ip-prefix-name | route-policy route-policy-name }
import
By default, IS-IS accepts all
routes calculated using
received LSPs.
Filtering redistributed routes
IS-IS can redistribute routes from other routing protocols or other IS-IS processes, add them into the IS-IS
routing table, and advertise them in LSPs.
Perform this task to filter redistributed routes. Only routes not filtered can be added into the IS-IS routing
table and advertised to neighbors.
To configure the filtering of redistributed routes:
Ste
p
Command
Remarks
1. Enter system view.
system-view N/A
2. Enter IS-IS view.
isis [ process-id ] [ vpn-instance vpn-instance-name ]
N/A
3. Filter routes redistributed
from another routing
protocols or IS-IS process.
filter-policy { acl-number | ip-prefix ip-prefix-name
| route-policy route-policy-name } export [ protocol
[ process-id ] ]
By default, IS-IS
accepts all
redistributed routes.
Configuring IS-IS route leaking
Perform this task to configure IS-IS to advertise routes from Level-2 to Level-1.
Follow these guidelines when you configure IS-IS to advertise routes from Level-2 to Level-1
• If a filtering policy is specified, only routes passing the filtering policy can be advertised into Level-1.
• If a routing policy is used, the routing policy must be specified in the import-route isis level-2 into
level-1 command to filter routes from Level-2 to Level-1. Other routing policies that are specified to
filter inbound or redistributed routes cannot filter routes advertised from Level-2 to Level-1.
To configure IS-IS route advertisement: