This field controls the operation of the alternative local AS number specified by the bgpPeerConfAltLocalAs field. It has no effect unless bgpPeerConfAltLocalAs specifies a valid non-zero value. This field controls the use of the alternative local AS number in the following BGP operations: - establishing the peering session - updating the AS_PATH when importing a route received from the peer (EBGP only) - updating the AS_PATH when exporting a route to the peer (EBGP only). These operations are described in full in the BGP Configuration and Management Guide (bgp_config_mgmt.doc) and summarized in the following table. Mode |Session |AS_PATH In|AS_PATH Out ============+==========+==========+================== Standard BGP|Primary AS|- |Primary AS Mode 1 |Either |- |Selected As Mode 2 |Alt AS |Alt AS |Alt AS, Primary AS Mode 3 |Alt AS |- |Alt AS, Primary AS Mode 4 |Alt AS |- |Alt AS. This field can be changed at any time. However, if the field is changed while the peer is admin_status UP, the change will only take effect after the peer has been cycled admin_status DOWN and then UP, thus forcing the peer session to be restarted. In this case, until the peer is set admin_status DOWN, the peer will be marked as out of date (as reported by the config_state field in the AMB_BGP_PEER_STATUS row for the peer).