Merit Networking USC/ISI Ripe-181 [Bates et al., 1994] is a language to specify routing policy constraints for inter-domain routing in the Internet. Ripe-181 allows the specification of both import policy constraints (by specifying as-in and interas-in attributes) and export policy constraints (by specifying as-out and interas-out attributes). There are limitations in the types of preference and access control policies that can be described by RIPE-181 and the limitations became evident when several enterprises tried to use RIPE-181 to describe their routing policies. One such limitation is the lack of ability to specify autonomous-system path expressions, henceforth referred to as AS path expressions, in the policy attributes (i.e. as-in, interas-in, as-out and interas-out attributes). This document extends Ripe-181 to enable the specification of AS path expressions in the aut-num objects. It is assumed that the reader is familiar with Ripe-181.