 Act applied only to incumbent local telephone companies that provided "telephone exchange service," which is the use of the local telephone network to reach other local customers, or "exchange access," which is the use of the local telephone network to connect to long distance providers to reach long distance customers. The FCC's Advanced Services Order concluded that DSL service constituted either telephone exchange service or exchange access (without resolving into which category DSL service fell) and thus was subject to the 1996 Act's resale, interconnection, UNE access, and collocation mandates. The order also initiated a rulemaking seeking comment on precisely how to apply these resale, unbundling, and collocation requirements and proposing that DSL be allowed to avoid the restrictions imposed incumbent local telephone companies SO long as they provided service through a separate subsidiary (FCC 1998f). After US West sought judicial review of the Advanced Service Order, the FCC moved to remand the matter voluntarily SO that it could consider the arguments raised in US West's brief.1 On remand, the FCC reaffirmed its conclusion that DSL represented either telephone exchange service or exchange access (FCC 1999f). On judicial review, the D.C. Circuit vacated and remanded the order. Agency and judicial precedent dictated that telephone exchange service and exchange access represent exclusive categories that occupy the entire field and thus that traffic had to be classified as either local or long distance. The FCC's failure to resolve into which category DSL properly fell represented a want of reasoned decisionmaking sufficient to justify invalidating the agency's action (WorldCom, Inc. V. FCC, 246 F.3d 690, 695-96 (D.C. Cir. 2001)). The FCC has also struggled to determine precisely which DSL-related network elements are subject to the 1996 Act's UNE access requirements. Initially, the agency adopted a permissive, if somewhat grudging, stance. Because the statute limits UNE access to elements used in telephone