Abstract: The routing problem of inter-domain composed service based on overlay network was deeply researched．Since the strategy-routing policy affects a lot on the inter-domain routing,the multi-goals optimal model with multi-constraints was built on the inter-domain composed service routing．The layered algorithm was adopted to solve the function constraint of optimal model,and then the improved ants algorithm was employed to solve this problem in the la-yered model．The simulation shows the non-dominants solutions are evenly distributing,which means the algorithms perform well and the inter-domain routing method based on overlay network is feasible.

Key words: Overlay network,Service composition,Layered algorithm,Ants algorithm,Composition optimization