TP-Link T2600G-18TSTL-SG3216 T2600G-18TSUN V1 Configuration Guide - Page 325

Configuring Spanning Tree Spanning Tree If the switch cannot receive BPDUs because of link congestions or link failures, the root port will become a designated port and the alternate port will transit to forwarding status, so loops will occur. With Loop Protect function enabled, the port will temporarily transit to blocking state when the port does not receive BPDUs. After the link restores to normal, the port will transit to its normal state, so loops can be prevented. »» Root Protect Root Protect function is used to ensure that the desired root bridge will not lose its position. It is recommended to enable this function on the designated ports of the root bridge. Generally, the root bridge will lose its position once receiving higher-priority BPDUs caused by wrong configurations or malicious attacks. In this case, the spanning tree will be regenerated, and traffic needed to be forwarded along high-speed links may be lead to low-speed links. With root protect function enabled, when the port receives higher-priority BDPUs, it will temporarily transit to blocking state. After two times of forward delay, if the port does not receive any higher-priority BDPUs, it will transit to its normal state. »» BPDU Protect BPDU Protect function is used to prevent the port from receiving BPUDs. It is recommended to enable this function on edge ports. Normally edge ports do not receive BPDUs, but if a user maliciously attacks the switch by sending BPDUs, the system automatically configures these ports as non-edge ports and regenerates the spanning tree. With BPDU protect function enabled, the edge port will be shutdown when it receives BPDUs, and reports these cases to the administrator. Only the administrator can restore it. »» BPDU Filter BPDU filter function is to prevent BPDU flooding in the network. It is recommended to enable this function on edge ports. If a switch receives malicious BPDUs, it forwards these BPDUs to the other switches in the network, and the spanning tree will be continuously regenerated. In this case, the switch occupies too much CPU or the protocol status of BPDUs is wrong. With BPDU filter function enabled, the port does not receive or forward BPDUs, but it sends out its own BPDUs, preventing the switch from being attacked by BPDUs. »» TC Protect TC Protect function is used to prevent the switch from frequently removing MAC address entries. It is recommended to enable this function on the ports of non-root switches. Configuration Guide 295