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Configuring is-is route filtering, Filtering routes calculated from received lsps, Filtering redistributed routes – H3C Technologies H3C SR8800 User Manual

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Step 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.

Redistribute routes
from another

routing protocol.

import-route protocol [ process-id |
all-processes | allow-ibgp ] [ cost cost |
cost-type { external | internal } | [ level-1 |

level-1-2 | level-2 ] | route-policy

route-policy-name | tag tag ] *

By default, no route is
redistributed.
If no level is specified, routes are

redistributed into the Level-2
routing table by default.

4.

Configure the

maximum number

of redistributed
Level 1/Level 2

IPv4 routes.

import-route limit number Optional.

NOTE:

Only active routes can be redistributed. Use the display ip routing-table protocol command to display
route state information.

Configuring IS-IS route filtering

You can reference a configured ACL, IP prefix list, or routing policy to filter routes calculated from the

received LSPs and the routes redistributed from other routing protocols.

Filtering routes calculated from received LSPs

IS-IS saves the 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.
By referencing a configured ACL, IP prefix list or routing policy, you can filter the calculated routes. Only

the routes matching the filter can be added into the IS-IS routing table.
To filter routes calculated from received LSPs:

Step 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, no filtering is
configured.

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.
By reference a configured ACL, IP prefix list or routing policy, you can filter redistributed routes and only
the routes matching the filter can be added into the IS-IS routing table and advertised to neighbors.
To configure the filtering of redistributed routes: