, the traffic patterns are likely to be quite similar to those already in the network, and thus retail access may have only a minimal impact on the network's optimal configuration. Retail access also obviates the need for carriers to negotiate service contracts with each customer. In addition, because all of the traffic travels through a single network, the network owner should be able to obtain all of the information it needs to determine the optimal configuration fairly easily. To our knowledge, no court has ever mandated retail access under the essential facilities doctrine. As noted earlier, the essential facilities doctrine requires that network owners provide competitors with access to the services of bottleneck inputs. Retail access, in contrast, provides customers with access to the services provided by the entire network. Indeed, retail access does not fit naturally with any aspect of antitrust law. As noted earlier, antitrust law does not impose liability on firms For an overview of price discrimination, see generally Varian (1989). Networks in Telecommunications that obtain monopolies through natural features of the market. 99 In the words a leading court of appeals decision on the subject, "a natural monopoly market does not of itself impose restrictions on one who actively, but fairly, competes for it, any more than it does on one who passively acquires it" (Union Leader Corp. V. Newspapers of New England, Inc., 284 F.2d 582, 584 (1st Cir. 1960)). To hold otherwise, in the words of another leading court of appeals decision, would be to "require the impossible - a competitive market under conditions of natural monopoly" (Omega Satellite Prods. Co. V. City of Indianapolis, 694 F.2d 119, 126 (7th Cir. 1982)). 100 In the absence of other anticompetitive behavior, such firms are generally free to charge the full monopoly price and to refuse to deal with whomever they wish. Indeed, if the market is a natural monopoly, retail access would simply dictate how the output of the monopoly is distributed. Not onl