基于地址转发表的链路层拓扑发现算法

Network link layer topology discovery algorithm based on address forwarding table

为了发现链路层网络拓扑结构,基于地址转发表提出了一个算法。算法分析了生成树中交换机下行端口地址转发表,按照交换机间直接连接规则确定交换机间的端口连接关系,对于不满足直接连接规则的交换机端口对,将待确定连接关系交换机的下行端口中记录的所有交换机分割成互不相交的子树,该下行端口即通过不可网管设备(如hub)与这些子树的根节点相连。测试结果表明,算法不仅能发现交换机间的连接关系,还能发现hub等不可网管设备的存在,适合异构网络的拓扑发现。

To discover link layer network topology, an algorithm is proposed based on address forwarding table. Through analyzing down-port AFTs （address forwarding table）, the algorithm discovered switch links according to the direct link rules, and for the port pairs did not meet direct link rules, we partitioned the switches into several sub trees, each of them didn＇t intersect with others, thus, we could determine that there were dummy nodes. The test shows that the algorithm can not only discover links between switches but also could discover the unmanaged device, such as hub, etc., so the algorithm can be used to discover heterogeneous switched network topology.