Using XPL to Filter the BGP Routes to Be Received

A BGP device can use a route-filter to filter the routes to be received and modify route attributes to control the network traffic forwarding path.

Usage Scenario

BGP is used to transmit routing information between ASs, and route advertisement directly affects traffic forwarding.

A BGP device may receive multiple routes to the same destination network from different peers. To control the network traffic forwarding path, filter the routes to be received.

In addition, a BGP device may receive a large number of routes during an attack, which may consume lots of device resources. In this case, the administrator must limit the resource consumption based on the network planning and device performance.

You can use XPL route-filters to control the BGP routes to be received from all peers or peer groups or from a specified peer or peer group.

Pre-configuration Tasks

Before using XPL to filter the BGP routes to be received, configure basic BGP functions.

Procedure

Use XPL to filter the BGP routes to be received from all peers or peer groups.
Perform the following steps on the BGP device:
1. Run system-view
  The system view is displayed.
2. Run bgp { as-number-plain | as-number-dot }
  The BGP view is displayed.
3. Run ipv4-family unicast
  The IPv4 unicast address family view is displayed.
4. Run route-filter route-filter-name import
  The BGP device is configured to filter the routes to be received from all peers or peer groups.
5. Run commit
  The configuration is committed.
Use XPL to filter the BGP routes to be received from a specific peer or peer group.
Perform the following steps on the BGP device:
1. Run system-view
  The system view is displayed.
2. Run bgp { as-number-plain | as-number-dot }
  The BGP view is displayed.
3. Run ipv4-family unicast
  The IPv4 unicast address family view is displayed.
4. Run peer { group-name | ipv4-address } route-filter route-filter-name import
  The BGP device is configured to filter the routes to be received from the specified peer or peer group.
5. Run commit
  The configuration is committed.

Checking the Configuration

Run the following commands to check configurations:

Run the display xpl route-filter state [ attached | unattached ] command to check information about the configured route-filter.
Run the display bgp routing-table [ peer ipv4-address received-routes [ statistics ] ] command to check the routes in the BGP routing table.