In this paper we propose overlap-aware path selection and dynamic packet distribution due to failure detection in multipath routing overlay network. Real-time communications that utilize UDP do not ensure reliability for realizing fast transmission. Therefore congestion or failure in a network deteriorates the quality of service significantly. The proposed method seeks an alternate path that hardly overlaps an IP path so as to improve its reliability. The proposed method also detects congestion or failure by differential of packet loss rate and apportion packets to the IP path and the alternate path dynamically. Evaluation on PlanetLab shows the proposed method avoids congestion Consequently the influence of congestion and failure lessens and the proposed multipath routing improves the reliability which can be used for real-time communications.