'no-prepend-replace-as-dual-as:' The session can be established using either primary-as or alternate local-as. Selected-as is not prepended to the inbound AS_PATH list, but prepended to outbound AS_PATH list. 'no-prepend-replace-as': The session is established via alternate local-as. Both the alternate-as and primary-as are not prepended to the inbound AS_PATH list, but alternate local-as is prepended to the outbound AS_PATH list. 'no-prepend': The session is established via alternate local-as. Both the alternate-as and primary-as are not prepended to the inbound AS_PATH list, but prepended to the outbound AS_PATH list. 'none': The session is established via alternate local-as. Both the alternate-as and primary-as are prepended to both the inbound and the outbound AS_PATH list.