ers means that sys- tems already exist for placing orders and requesting service, wholesale access would still require that these systems be redesigned to make them accessible to outside personnel. The complexity of this analysis is demonstrated by the variety of distribution channels employed by the wireless industry, described in Chapter 8. This system of "dual distribution," in which output is sold simultaneously through company- owned and independent retailers, can reduce distribution costs, encourage the provision of presale services, and provide manufacturers with better information about customers' responses to their products. Although dual distribution systems have sometimes raised anticompetitive concerns, commentators generally agree that such concerns are misplaced. In the words of one leading antitrust scholar: A manufacturer who has no market power cannot use dual distribution to cre- ate it. Furthermore, even a monopoly manufacturer generally cannot increase Networks in Telecommunications its market power by insulating its wholly-owned retail outlets, even if the effect is to injure competing, independent retailers. If the manufacturer has market power, any monopoly profits earned at the retailer level could also be earned at the manufacturer level. (Hovenkamp 2005, p. 490) At the same time, dual distribution systems are less vulnerable to collusion, since concerns about double marginalization will give the manufacturer-owned outlets no incentive to participate in a cartel seeking to create market power at the retail level. That said, dual distribution systems are more vulnerable to free riding, because independent dealers will recognize that retail outlets owned by the manufacturer are essentially guaranteed to provide the full range of presale services. It is reasonable to expect manufacturers employing dual distribution systems to impose territorial restrictions on independent retailers and mandate a degree of exclusivity in order to protect against free riding (Hovenkamp 2005, p. 490). The exten