If part of your problem is structured as a network, then you may want to consider calling the ILOG CPLEX Network Optimizer. This optimizer may have a positive impact on performance. There are two alternative ways of calling the network optimizer:

How much performance improvement you observe between using only a simplex optimizer versus using the network optimizer followed by either of the simplex optimizers depends on the number and nature of the other constraints in your problem. On a pure network problem, performance has been measured as 100 times faster with the network optimizer. However, if the network component of your problem is small relative to its other parts, then using the solution of the network part of the problem as a starting point for the remainder may or may not improve performance, compared to running the primal or dual simplex optimizer. Only experiments with your own problem can tell.