resented in Figure 2.6, except that now a competitor has obtained access to six units of the capacity of the link connecting nodes cand e (marked on the graph with a circle). From the perspective of the network owner, this has the effect of reduc- ing the effective capacity of that link by that amount. In this case, the magnitude 7 If the network is not operating at full capacity, the optimization problem instead focuses on identifying the minimum-cost flow and requires a slightly different approach (Fleischer 2004). Networks in Telecommunications of this reduction causes the links composing the minimum cut to change to the ones portrayed by the line marked D. As a result, granting a competitor access to a link that was not part of the minimum cut (and thus had slack in its capacity) nonetheless reduces the effective capacity of the entire network. The amount of reduction is not necessarily equal to the magnitude of the access granted. Instead, the amount of reduction depends upon the configuration of the particular network involved. In the situation portrayed in Figure 2.7, the impact of allowing a com- petitor to occupy six units of capacity in the link connecting node with node e is to reduce the effective capacity of the entire network by two. The value of carrying two units from node S to node t represents the opportunity cost of granting this competitor access to the link between nodes C and e. In addition, the change in direct costs associated with granting access can be determined by recalculating the flow passing along each noncritical link when the postaccess network is operating at full capacity. At the same time, it is quite possible that granting access to a particular link might have no effect on the total carrying capacity of the network. Whether that is the case depends on how much slack exists in the link to which access is being granted. If the link to which access is being granted is not part of the minimum cut and the additional reduction in capacity does not make it part of the minimum cut, g