基于AFT满足下行约束的物理拓扑发现方法

物理拓扑发现对于网络管理和应用具有重要意义，基于地址转发表的物理拓扑发现是目前学术界研究的热点问题.但由于实际网络的地址转发表通常不完整，导致了物理拓扑发现的难度，本文基于降低在实际拓扑发现时对AFT完整性的要求，定义了地址转发表的三类约束，并提出了地址转发表满足下行约束的树型剪裁算法，用于发现子网的物理拓扑结构.算法极大地降低了拓扑发现对地址转发表完整性的要求，是对仅通过下行端口地址转发表进行拓扑发现的最松约束.模拟仿真实验验证了算法的正确性和高效性，算法在实际网管系统中的部署进一步验证了算法在真实网络环境中的实用性.

A Physical Topology D iscovery Method Based on AFT of D ownstrea m Constraint

Network physical topology discovery is very important for network management and application,the physi-cal topology discovery based on AFT is a hot topic on current study.However,the incomplete AFT of network nodes in real network leads to the hardness of physical topology discovery.Based on decreasing the demand for the completeness of AFT in topology discovery,this paper defines three constraints of AFT,and proposes a tree-chopping algorithm based on AFT sat-isfying downstream constraint to discover the physical topology of a subnet.The proposed algorithm decreases the constraints for the completeness of AFT greatly,and demands the loosest constraint in physical topology discovery relying solely on downstream ports.The correctness and efficiency of the proposed algorithm is verified by the simulation experiment,and the algorithm applicability to real network is verified by deploying the algorithm in a real network management system.