Figure 21 TC snooping application scenario
In the network, Device A transparently transmits the received STP BPDUs and does not participate in STP
calculations. When a topology change occurs to the customer networks, Device A might need a long
time to learn the correct MAC address table entries and ARP entries, affecting forwarding of service
traffic. To avoid the problem, you can enable TC snooping on Device A.
TC snooping enables a device to actively clear the MAC address table entries and ARP entries upon
receiving TC-BPDUs and to re-learn the MAC address table entries and ARP entries, so that the device
can normally forward the user traffic.
Disable STP globally.
Configuring TC snooping
Perform the TC snooping configuration on Device A shown in
Follow these steps to configure TC snooping:
Enter system view
Enable TC snooping
TC snooping and STP are mutually exclusive.
TC snooping does not take effect on the ports on which BPDU tunneling is enabled for STP. For more
information about BPDU tunneling, see the chapter "BPDU tunneling configuration."
For more information about ARP, see the
For more information about MAC address table entries, see the chapter "MAC address table
Use the command...
Layer 3—IP Services Configuration Guide
Disabled by default.