Configuring Tc-Bpdu Transmission Restriction; Enabling Tc-Bpdu Guard - HP FlexFabric 12900 Series Configuration Manual

Step
3. Enable port role restriction.

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
1. Enter system view.
2. Enter Layer 2 Ethernet or
aggregate interface view.
3. Enable TC-BPDU 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 and be 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. HP recommends that you enable TC-BPDU
guard.
To enable TC-BPDU guard:
Step
1. Enter system view.
2. Enable the TC-BPDU guard function.
Command
stp role-restriction
Command
system-view
interface interface-type
interface-number
stp tc-restriction
Command
system-view
stp tc-protection
107
Remarks
By default, port role restriction is
disabled.
Remarks
N/A
N/A
By default, TC-BPDU transmission
restriction is disabled.
Remarks
N/A
By default, TC-BPDU guard is
enabled.
HP recommends not
disabling this feature.