An optimized Chord protocol is proposed to solve the convergence problem for separated Chord rings over mobile Ad-hoc networks (MANETs). This protocol exploits the information of topological neighbors in routing layer by utilizing a cross-layer design,and periodically detects whether there is any neighbor node that belongs to an alien Chord ring by sending detecting packets. The detection will be confirmed and then the corresponding predecessor node will be found out to initialize convergence of the Chord rings. Theoretical analysis and experiment results show that the proposed algorithm can detect separated Chord rings and implement the convergence process efficiently,and that a significant improvement in the successful lookup ratio is also achieved at an acceptable overhead for the system maintenance. Moreover,the proposed protocol can ensure the stability and scalability of the system. An optimized Chord protocol is proposed to solve the convergence problem for separated Chord rings over mobile Ad-hoc networks (MANETs). This protocol exploits the information of topological neighbors in routing layer by utilizing a cross-layer design, and periodically detects whether there there is any neighbor node that belongs to an alien Chord ring by sending detecting packets. The detection will be confirmed and then the corresponding predecessor node will be found out to initialize convergence of the Chord rings. Theoretical analysis and experiment results show that the proposed algorithm can detect separated Chord rings and implement the convergence process efficiently, and that a significant improvement in the successful lookup ratio is also achieved at an acceptable overhead for the system maintenance. Moreover, the proposed protocol can ensure the stability and scalability of the system.