This string identifies a BGP AS-path regular expression, defined elsewhere in csRtPolicyExpTable, that this policy term uses as a match condition; a NULL string means this term does not filter on AS path. An admin references a named AS-path expression here to match routes whose path traversed particular autonomous systems. For example, setting csRtPolicyTermFromBgpASPathName to 'transit-provider-path' matches only routes whose AS path matches that previously defined regular expression.