Firstly. the proactive policy to ALM tree which is based on Chord DHT was extended and a back-path scheme with which each node pre-calculates a backup path for itself was proposed. When the non-leaf node leaves. all its child nodes can switch to the respective backup path immediately. https://www.roneverhart.com/2018-NISSAN-SENTRA-Windshield-Wiper-Arm-with-Blade-Frameless-Pair-Left-and-Right/