The main function of Spanning Tree Algorithm (STA) is to eliminate loops caused by redundant links in bridge networks. Spanning Tree Protocol (STP) works at the second layer of the OSI model and ultimately determines which data ports to forward and block traffic by exchanging Bridge Protocol Data Units (BPDUs) between bridges. This protocol will cause errors under certain special circumstances, and it is also very difficult to detect the point of failure based on the design of the network at that time. We can only say that in this case, we should try to avoid similar phenomena from happening. Often errors in the spanning tree algorithm will result in bridging loops. It is generally believed that Layer 2 link loops are caused by bugs in device hardware or system software. In fact, this is not the case. The cause of Layer 2 link loops is mainly caused by a data port that should be in the blocked state transitioning to the forwarding state. There are many reasons for Layer 2 link loops. Most of them will cause a large number of BPDUs to be lost, causing the port that should be in the blocking state to transition to the forwarding state, eventually leading to a Layer 2 link loop. ? Duplex Mismatch Duplex mismatch configuration errors often occur on a point-to-point link. Especially when one end of the link is forced to full duplex. If the other end is still in auto-negotiation mode, eventually, the port will be in half-duplex mode (it will no longer negotiate when the port is forced to full-duplex).
