apply comm-filter delete

The community attribute is a private attribute of BGP, and the apply comm-filter delete command is valid only for BGP routes.

When the apply comm-filter delete command is run in the Route-policy view to delete the values from the community filter, only one community attribute can be specified in the ip community-filter command. If multiple community attributes are configured in the same community filter, running the apply comm-filter delete command cannot delete these community attributes. To delete the community attributes, you need to run the ip community-filter command several times to configure community attributes one by one, and then run the apply comm-filter delete command to delete these community attributes.

• Run the route-policy command to enter the route-policy view.
• A route-policy may consist of multiple nodes. The relationship between the nodes is "OR". The system matches a route against the nodes in sequence. If the route matches a node, the route matches the route-policy, and the system no longer matches it against other nodes.
• Each node comprises a set of if-match and apply clauses. The if-match clauses define the filtering rules that are used to match certain route attributes. The relationship among if-match clauses of the same node that are based on different route attributes is AND. A route matches a node only when the route matches all the filtering rules specified in the if-match clauses of the node. The apply clauses specify actions. The relationship among if-match clauses of the same node that are based on the same route attribute is OR. The system matches routes against the if-match clauses in order. If a route matches an if-match clause, the system no longer matches the route against the rest if-match clauses. For example, the if-match community-filter 1 and if-match as-path-filter 1 configurations in node 10 are based on different route attributes. Therefore, the relationship among if-match clauses of this node is AND. The if-match community-filter 1 and if-match community-filter 2 configurations in node 20 are both based on the community attribute. Therefore, the relationship among if-match clauses of this node is OR. The apply clauses specify actions. If a route matches a node, the apply clauses set some attributes for the route.

1. Only one community attribute can be configured for the specified community attribute list. To delete multiple community attributes, configure multiple community attribute lists. For example, if community attribute list 1 is used to delete 100:100 200:200 from the community attribute 100:100 200:200 300:300 carried in a route, perform the following configurations on community attribute list 1:
   [~HUAWEI] ip community-filter 1 permit 100:100
   [*HUAWEI] ip community-filter 1 permit 200:200
   [*HUAWEI] display ip community-filter
   Community filter Number: 1
   index: 10 permit 100:100
   index: 20 permit 200:200
   [~HUAWEI] route-policy RP1 permit node 10
   [*HUAWEI-route-policy] apply comm-filter 1 delete
   While in the following case, you cannot delete the community attributes 100:100 and 200:200.
   [*HUAWEI] ip community-filter 1 permit 100:100 200:200
   [*HUAWEI] display ip community-filter
   Community filter Number: 1
   index: 30 permit 100:100 200:200
   [~HUAWEI] route-policy RP1 permit node 10
   [*HUAWEI-route-policy] apply comm-filter 1 delete
2. When the apply community and apply comm-filter delete commands are run on the same node in a route-policy, the system performs the delete operation before the set operation regardless of the sequence in which the two commands are run.

<h1 id="the-following-shows-the-route-policy-named-rp1">The following shows the Route-Policy named RP1.</h1>

[*HUAWEI] display route-policy

Route-policy: RP1

permit : 10 (matched counts: 0)

Apply clauses:

apply comm-filter 1 delete

apply community 999:9 additive

<h1 id="the-following-shows-the-community-filter-1">The following shows the community-filter 1.</h1>

[*HUAWEI] display ip community-filter

Community filter Number: 1

index: 10 permit 111:1

index: 20 permit 999:9

In this case, When you use the Route-Policy named RP1 to filter BGP routes, the community attribute 111:1 of the corresponding BGP routes is deleted and the community attribute 999:9 is added.