STP Advanced Features and Variants 3

Question 1

Which STP protection feature should be enabled on all access ports connected to end devices to prevent them from participating in STP topology changes?

Accepted Answer

BPDU Guard

Answer

BPDU Guard disables a PortFast-enabled port if any BPDU is received, protecting the STP topology from rogue switches.

Question 2

What does the STP Backbone Fast feature do when an indirect link failure is detected?

Accepted Answer

Allows a switch to use an alternate port without waiting for MaxAge by sending RLQ messages

Answer

Backbone Fast uses Root Link Query (RLQ) messages to verify if the root is still reachable via upstream switches, cutting MaxAge wait time.

Question 3

STP UplinkFast is most beneficial in which network scenario?

Accepted Answer

Access layer switches with one uplink active and one in blocking state

Answer

UplinkFast allows an access-layer switch to immediately activate a blocking uplink port upon loss of the active uplink, bypassing listening/learning states.

Question 4

In MSTP, what is IST (Internal Spanning Tree)?

Accepted Answer

Instance 0 inside an MST region that carries unassigned VLANs and connects to the CIST

Answer

The IST is MST instance 0 within a region; it carries all VLANs not explicitly mapped to other instances and connects the region to the CIST.

Question 5

Which RSTP port role forwards traffic and is elected based on lowest path cost to the root bridge?

Accepted Answer

Root Port

Answer

The Root Port is the port on a non-root switch with the lowest cumulative path cost to the root bridge, and it forwards traffic toward the root.

(STP) Spanning Tree Protocol Practice Test

(STP) Spanning Tree Protocol Practice Test

STP Advanced Features and Variants 3