olved the Supreme Court and Congress, retail access to interstate services is now provided on a nontariffed basis (Schoenwald 1997; Huber et al. 1999). In telecommunications, retail access is sometimes accompanied by regulation of retail rates charged. For example, retail rates for local wireline telephone service are regulated. As noted in the previous chapter, the traditional approach assesses the reasonableness of a particular rate in light of the carrier's historical costs. Because the retail rates tend to be uniform throughout the service area, customers in low- cost areas implicitly cross-subsidize customers in high-cost areas. Retail rates for emerging services, such as wireless telephony and digital subscriber lines, tend not to be regulated. 2. Wholesale Access Mandated wholesale access gives purchase rights to a network owner's competitors, who can then resell network services to end users. Wholesale access involves the same services as retail access, but the party obtaining access is different. In retail access, access is provided to the customer. In wholesale access, access is provided to a competitor. It also differs from unbundled access in that the network's elements are kept together and purchased as a whole. Incumbent telecommunications firms voluntarily provide wholesale access ser- vices to a wide range of local, national, and international companies, including competitive local exchange carriers (CLECs) with or without their own facili- ties, long-distance carriers (known as interexchange carriers or IXCs), interna- tional long-distance carriers, wireless carriers, enhanced service providers (ESPs), Internet service providers (ISPs), and national resellers. For example, Qwest offers what it terms wholesale products in the following categories: combined access and transport, billing, customer premises equipment, interconnection facility-based, interexchange access, Internet and data, resale, non-facility-based, voice solutions, and wireless. In the most basic wholesale category of switched acce