Nowadays there is an intense development of corporate networks of various configurations with the usage of different routing protocols. At the same time the role of the telecommunication network of special purpose is increasing, which is widely used in the interests of state structures and has a significant potential for satisfaction of corporate interests. However, the configuration of their common use requires the adjustment (redistribution) of routing protocols, which takes a great amount of time in network administrators. In this case, as a rule, administrators do not perform counting of the composite route metric, and the values are set by default. It leads to incorrect setting of the metric with mismatch of the actual cost of the route. To solve this problem, in particular providing of the formation of rational values of route metrics in case of their redistribution between autonomous systems in multiprotocol transmission networks with help of the emulator, two networks with 50 routers are recreated. There different routing protocols are used and a detailed analysis of the metrics is held. Under the metric is understood the conditional cost, which is used by the routers to select the optimal route in the presence of two or more different routes to the final network, including using different routing protocols. The administrative distance is a parameter that characterizes the reliability of the route information source. Each routing protocol is assigned a priority of trustiness (reliability), from maximum to minimum, indicated by the value of the administrative distance. The metric calculation process is significantly different for various routing protocols. There are protocols where the metric value is determined by simple counting of the number of receivers to the final network.However, there are such where the calculation is made using five parameters, namely the following: throughput, delay, reliability, load and payload size. As a result of the research, real values of route metrics with different routing protocols and the number of used routers are determined. It allowed us to offer a generalized formula for calculating a rational metric and an administrator's algorithm for the correct configuration of the interaction of networks with different routing protocols and structure. The application of the algorithm allows to provide the formation of rational values of route metrics when realisation their redistribution between autonomous systems in multiprotocol transmission networks.