3Com Switch 8800 Configuration Guide Chapter 38 MSTP Region-configuration38-32Operation CommandConfigure TC protection of the switch (fromsystem view) stp tc-protection enableDisable TC protection (from system view) stp tc-protection disableBy default, only the protection from TC-BPDU packet attack is enabled on the switch.BPDU protection, Root protection and loop protection are disabled.After configured with BPDU protection, the switch will disable the edge port throughMSTP which receives a BPDU, and notify the network manager at same time. Theseports can be resumed by the network manager only.The port configured with Root protection only plays a role of designated port on everyinstance. Whenever such port receives a higher-priority BPDU, that is, it is about to turninto non-designated port, it will be set to listening state and not forward packets anymore (as if the link to the port is disconnected). If the port has not received anyhigher-priority BPDU for a certain period of time thereafter, it will resume the normalstate.For one port, only one configuration can be effective among loop protection, Rootprotection and Edge port configuration at the same moment.Note:The port configured with loop protection can only turn into discarding state on everyinstance. That such a port receives no configuration message for a long time indicatesthat it is about to change its state and role. Only the port role changes but the portdiscarding state remains unchanged, and no packets are forwarded. In this way, if thepeer end cannot send BPDU packets due to error operation, and the port entersforwarding state directly for not receiving configuration message for a long time, no loopwill be generated by enabling the loop protection.By default, the switch does not enable BPDU protection or Root protection.38.2.17 Enabling/Disabling MSTP on the DeviceYou can use the following command to enable MSTP on the device.Perform the following configuration in system view.
