At the national level, Telecommunications systems are generally organized into several interconnected autonomous domains. When transmitting data between interconnected domains, the blocking probability of network can be high due to the complexity of management and management policies at the domain level. Therefore, the question it raises is how to optimize inter-domain routing between different autonomous systems? The optimization of the inter-domain routing can be realized from several criteria related to the interconnection links, namely: the fragmentation rate, the energy consumed, the link quality, the transmission delay, the blocking probability, and the service quality. In this work, we propose an interdomain routing algorithm for multi-domain elastic optical networks, and a model for managing fragmentation in the network to optimize resources utilization. The implementation of inter-domain routing requires the construction of sub-topologies from existing domain topologies and parameters such as fragmentation rate, link quality, energy consumption contrary to blocking probability which used in literature. These different contributions (CA-IL, CIL-TFM and CIL-CEM) based on parameters have allowed to optimize the use of the network resources, to reduce the consumed energy as well as the blocking probability of the network compared to existing model in the literature through the simulations that have been conducted. However, the CIL-TFM approach provides a better blocking probability than other approaches with less resources used, and more energy consumed. In the future, we intend to integrate an end-to-end delay management model to achieve optimal inter-domain routing with the parameters already used.