Configuring TC Protection on a Device
Context
A switch deletes its MAC address entries and ARP entries after receiving TC BPDUs. An attacker can use this to their advantage by sending a large number of bogus TC BPDUs to the switch in a short time, causing the device to frequently delete MAC address entries and ARP entries. This increases the load on the switch and threatens network stability.
After enabling TC BPDU protection on a switch, you can set a limit for the number of times the device processes TC BPDUs within a given time. If this number is exceeded, the switch processes only the specified number of TC BPDUs. Any excess TC BPDUs are processed in one go by the switch after the specified period expires. This function prevents the switch from frequently deleting its MAC address entries and ARP entries, reducing the load on the switch and guaranteeing network stability.
Procedure
- Run system-view
The system view is displayed.
- Run stp tc-protection
TC protection is enabled for the device.
By default, TC protection is disabled on a device.
- Run either or both of the following commands to configure TC protection parameters.
To set the time period during which the device processes the maximum number of TC BPDUs, run stp tc-protection interval interval-value.
By default, the time period is the Hello Time.
To set the maximum number of TC BPDUs that the device processes within a specified period, run stp tc-protection threshold threshold.
By default, a device processes one TC BPDU within a specified period.
There are two TC protection parameters: time period during which the device processes the maximum number of TC BPDUs and the maximum number of TC BPDUs processed within the time period. For example, if the time period is set to 10 seconds and the maximum number of TC BPDUs is set to 5, the device processes only the first five TC BPDUs within 10 seconds and processes the other TC BPDUs together 10 seconds later.
The device processes only the maximum number of TC BPDUs configured by the stp tc-protection threshold command within the time period configured by the stp tc-protection interval command. Other packets are processed after a delay, so spanning tree convergence speed may slow down.
- Run commit
The configuration is committed.
