Configuring Tc-Bpdu Transmission Restriction; Enabling Tc-Bpdu Guard - H3C S7500X Series Configuration Manual

Configuring TC-BPDU transmission restriction

CAUTION:
Enabling TC-BPDU transmission restriction on a port might cause the previous forwarding address
table to fail to be updated when the topology changes.
The topology change to the user access network might cause the forwarding address changes to the
core network. When the user access network topology is unstable, the user access network might
affect the core network. To avoid this problem, you can enable TC-BPDU transmission restriction on
a port. With this feature enabled, when the port receives a TC-BPDU, it does not forward the
TC-BPDU to other ports.
Make this configuration on the port that connects to the user access network.
To configure TC-BPDU transmission restriction:
Step
Enter system view.
1.
Enter Layer 2 Ethernet
2.
interface or Layer 2
aggregate interface view.
Enable TC-BPDU
3.
transmission restriction.

Enabling TC-BPDU guard

When a device receives topology change (TC) BPDUs (the BPDUs that notify devices of topology
changes), it flushes its forwarding address entries. If someone uses TC-BPDUs to attack the device,
the device will receive a large number of TC-BPDUs within a short time. Then, the device is busy with
forwarding address entry flushing. This affects network stability.
TC-BPDU guard allows you to set the maximum number of immediate forwarding address entry
flushes performed within 10 seconds after the device receives the first TC-BPDU. For TC-BPDUs
received in excess of the limit, the device performs a forwarding address entry flush when the time
period expires. This prevents frequent flushing of forwarding address entries. As a best practice,
enable TC-BPDU guard.
To enable TC-BPDU guard:
Step
Enter system view.
1.
Enable the TC-BPDU guard feature.
2.
(Optional.) Configure the maximum
3.
number of forwarding address entry
flushes that the device can perform
every 10 seconds.
Command
system-view
interface interface-type
interface-number
stp tc-restriction
Command
system-view
stp tc-protection
stp tc-protection threshold
number
49
Remarks
N/A
N/A
By default, TC-BPDU transmission
restriction is disabled.
Remarks
N/A
By default, TC-BPDU guard
is enabled.
As a best practice, do not
disable this feature.
The default setting is 6.