ferentiation allow the network to provide new services that depend on a different network architecture, but also it allows multiple players to survive notwithstanding Networks in Telecommunications the presence of supply-side and demand-side economies of scale through a niche strategy that targets subsegments of the market that place a particularly high value on different types of network services. The result is not the promotion of vertical competition in which a succession of monopolists compete for the market, but rather the enhancement of more conventional horizontal competition in which multiple providers compete in the market (Yoo 2005). Interconnection access claims have not fared well under antitrust law, even when asserted against a dominant firm. For example, the literature often ignores the fact that MCI's private antitrust suit against AT&T involved two distinct essential facilities doctrine claims. The more celebrated claim, which we discuss in greater detail in the next section, involved what we call platform access, in which MCI sought access to a monopoly input controlled by AT&T (local telephone service) in order to sell a complementary service (long-distance telephone service). The often-overlooked claim is that MCI also sought to interconnect its long distance network with portions of AT&T's long distance network that reached areas that it did not yet serve. In this claim, MCI did not seek access to AT&T's network to sell complementary services. Instead, it sought connection with the larger network in order to sell the same services to similarly situated customers. Its concern was that its smaller network size put it at a competitive disadvantage. As a result, it sought interconnection to put itself on an equal footing with AT&T. The court of appeals overturned a jury verdict in favor of MCI on the interconnection access claim for the simple reason that "[t]here was no sufficient explanation as to why MCI, on the one hand, was building its own network, and, on the other, was entitled to access 