BPDU filter

Q: How deeply does Acing the CCNA Exam: Volume 1 Fundamentals and Protocols cover BPDU filter?

Explains both activation methods, port behavior, and loop risks, while recommending general avoidance.

As explained in Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

BPDU Filter is a spanning-tree feature that suppresses the sending or processing of Bridge Protocol Data Units on a switch port.

BPDU Filter suppresses Bridge Protocol Data Units on selected switch ports. It is useful where STP is unnecessary, such as ports connected to end hosts, but careless use can create Layer 2 loops. section 15.4.3

Choose the configuration method carefully:

Interface mode: spanning-tree bpdufilter enable prevents the port from sending BPDUs and makes it ignore received BPDUs, effectively disabling STP. section 15.4.3
Global PortFast mode: spanning-tree portfast bpdufilter default suppresses outgoing BPDUs on PortFast ports; receiving a BPDU disables PortFast and BPDU Filter, returning the port to normal STP or RSTP operation. section 15.4.3

Exam and operations warning

Applying interface-level BPDU Filter to a port connected to another switch can leave the port forwarding during a loop because STP cannot move it to discarding. Use the feature with extreme caution. section 15.4.3

How Acing the CCNA Exam: Volume 1 Fundamentals and Protocols covers it

Cover of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

liveBook manning.com

Read Acing the CCNA Exam: Volume 1 Fundamentals and Protocols on liveBook Get the book at manning.com

Related concepts

spanning-tree bpdufilter enableconfigured by · The spanning-tree bpdufilter enable command is a Cisco IOS interface-configuration command that enables BPDU Filter on a specific switch port.
bridge protocol data unituses · A bridge protocol data unit is a control message exchanged by spanning-tree-enabled switches to communicate topology information and determine port roles.
spanning tree protocolcontrasts with · Spanning Tree Protocol is a Layer 2 protocol that prevents bridged-network loops by selecting a loop-free topology and blocking redundant paths.
network loopcontrasts with · A network loop is a condition in which a packet circulates repeatedly among network devices without reaching its destination.
BPDU Guardcontrasts with · BPDU Guard is a switch-port protection feature that error-disables a port when it receives a Spanning Tree Protocol Bridge Protocol Data Unit.

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols. The section links point to the parts of the book it draws on.