Replacing an AS path

You can configure a routing policy where the AS path in matching routes is replaced by a list of AS numbers specified in the policy. For routes that match the policy, the current AS path is deleted and replaced with an AS_SEQ element containing the AS numbers listed in the policy in their configured sequence.

If you configure an empty AS list in the policy, then the current AS path in a matching route is deleted, and it would then have a null AS_PATH attribute.

The following is an example of a routing policy whose action is to replace the AS path in matching routes. 

--{ candidate shared default }--[  ]--
# info routing-policy
    routing-policy {
        policy policy02 {
            statement 100 {
                match {
                    protocol bgp
                }
                action {
                    bgp {
                        as-path {
                            replace [
                                12
                                13
                                14
                            ]
                        }
                    }
                }
            }
        }
    }