User's Manual

Table Of Contents
249
Users Manual of CS-6306R
20.1.2.4 Configuring BPDU Filter
When you globally enable BPDU filtering on Port Fast-enabled interfaces, it prevents interfaces that are in a
Port Fast-operational state from sending or receiving BPDUs. The interfaces still send a few BPDUs at link-up
before the switch begins to filter outbound BPDUs. You should globally enable BPDU filtering on a switch so
that hosts connected to these interfaces do not receive BPDUs. If a BPDU is received on a Port Fast-enabled
interface, the interface loses its Port Fast-operational status, and BPDU filtering is disabled.
Follow these steps to globally enable the BPDU filter feature.:
Command Purpose
spanning-tree portfast bpdufilter Globally enables bpdu filter feature. It is
valid to all interfaces.
no spanning-tree portfast bpdufilter Globally disables bpdu filter feature.
Instruction:
Globally enabling port fast feature may result in broadcast storm. The BPDU Guard or BPDU Filter should be
configured for protection sake.
Follow these steps to enable the BPDU filter feature in the interface configuration mode :
Command Purpose
spanning-tree bpdufilter enable Enables bpdu filter feature on the
interface.
spanning-tree bpdufilter disable Disables bpdu filter feature. It has no
effect on the global configuration.
no spanning-tree bpdufilter Disables bpdu filter feature. It has no
influence on the global configuration.
20.1.2.5 Configuring Uplink Fast
If a switch loses connectivity, it begins using the alternate paths as soon as the spanning tree selects a new
root port. By enabling UplinkFast with the spanning-tree uplinkfast global configuration command, you can
accelerate the choice of a new root port when a link or switch fails or when the spanning tree reconfigures
itself. The root port transitions to the forwarding state immediately without going through the listening and
learning states, as it would with the normal spanning-tree procedures.
Uplink Fast feature is only valid in SSTP/PVST mode.
Follow these steps to globally enable UplinkFast.:
Command Purpose
spanning-tree uplinkfast Enables uplink fast feature.
no spanning-tree uplinkfast Disables uplink fast feature.
20.1.2.6 Configuring Backbone Fast
BackboneFast is a complementary technology to the UplinkFast feature, which responds to failures on links