SDN Forwarding Path Consistent Update Strategy Based on Multi-rounds Update

• 1、School of Cyberspace Security, Beijing University of Posts and Telecommunications, Beijing 100876

Abstract：Software-Defined Networking (SDN) has the characteristics of forwarding and control separation. When the network needs to update the forwarding paths in data plane due to link congestion, link failure, or firewall rule adjustment, the controller will report to the relevant switches issue some new flow rules. However, due to the distributed nature of the data plane, the time for the update instructions to arrive at each switch and the time for each switch to complete the update operation are different, resulting in an unpredictable sequence for switches to complete update. Therefore, an intermediate path including forwarding loops may appear during the update period. Aiming at the problem of introducing temporary forwarding loopsduring the forwarding path update, in this paper, we propose an SDN forwarding path consistent update strategy based on multi-round update. The update process is distinguished according to the odd and even rounds. In odd rounds, we shorten the distance (hop) between the source and destination nodes of the forwarding path as much as possible. In even rounds, update all nodes that have deviated from the current forwarding path at one time. Perform the above two operations alternately until all nodes are updated.Experiment results show that the algorithm can effectively reduce the number of update rounds while ensuring that no forwarding loop occurs during the update period.

Keywords： Computer software Software-defined networking Path update Consistency Multiple rounds