Configuring a Policy for Advertising MBGP Routes

After MBGP filters the imported routes, only routes that pass the filtering are added to the local MBGP routing table and advertised to MBGP peers.

Context

MBGP can apply a routing policy to all routes to be advertised.

Procedure

Configure MBGP to filter all routes to be advertised.
1. Run system-view
  The system view is displayed.
2. Run bgp as-number
  The BGP view is displayed.
3. Run ipv4-family multicast
  The BGP-IPv4 multicast address family view is displayed.
4. Run filter-policy { acl-number | acl-name acl-name | ip-prefix ip-prefix-name } export [ protocol [ process-id ] ]
  A filtering policy is configured for routes to be advertised.
  - acl-number or acl-name acl-name: specifies an ACL.
  - ip-prefix-name: specifies the name of an IP prefix list.
  - export [ protocol [ process-id ] ]: filter routes to be advertised to any MBGP peers. After the filter-policy export command is used, MBGP filters routes to be imported by using the import-route command before importing them. Only routes that pass the filtering are added to the MBGP routing table and are advertised by MBGP.
5. Run commit
  The configuration is committed.
Configure MBGP to filter routes to be advertised to a specified peer or peer group.
1. Run system-view
  The system view is displayed.
2. Run bgp as-number
  The BGP view is displayed.
3. Run ipv4-family multicast
  The BGP-IPv4 multicast address family view is displayed.
4. Run the following commands as needed to configure MBGP to use different filters to filter routes to be advertised to a peer:
  - To use an ACL for route filtering, run:
```
peer { peer-address | group-name } filter-policy { basic-acl-number | acl-name acl-name } export
```
  - To use the AS_Path filter for route filtering, run:
```
peer { peer-address | group-name } as-path-filter { as-path-filter-number | as-path-filter-name } export
```
  - To use a prefix list for route filtering, run:
```
peer { peer-address | group-name } ip-prefix ip-prefix-name export
```
  A peer group and its members can use different export policies when advertising routes. This means that each member in a peer group can select its own policy when advertising routes.
5. Run commit
  The configuration is committed.