Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
An administrator wants a switchport connected to an end device to move to forwarding quickly but does not want that setting used on inter-switch links. Which feature is intended for that edge-port behavior?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
PortFast
This is correct because PortFast is intended for host-facing edge ports to speed their transition to forwarding.
B
Distractor review
Root guard
This is wrong because root guard protects against unexpected superior BPDUs but is not the edge-port fast-forwarding feature described.
C
Distractor review
Loop guard
This is wrong because loop guard addresses certain STP failure conditions, not normal host-port acceleration.
D
Distractor review
UDLD aggressive
This is wrong because UDLD is for unidirectional link issues, not the standard edge-port forwarding behavior in the question.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is selecting Root Guard or Loop Guard as the feature to speed up port forwarding. Both protect STP topology but do not affect how quickly a port transitions to forwarding. Another mistake is enabling PortFast on inter-switch links, which can cause network loops because those ports must participate fully in STP. Candidates may also confuse UDLD aggressive, which deals with unidirectional link failures, with PortFast’s role in fast edge-port forwarding. Understanding that PortFast is specifically designed to accelerate host-facing ports while excluding inter-switch links is critical to avoid these errors.
Technical deep dive
How to think about this question
PortFast is a Cisco Catalyst switch feature designed to optimize Spanning Tree Protocol (STP) behavior on edge ports connected directly to end devices such as PCs or printers. Normally, STP places ports in a listening and learning state for about 30 seconds each to prevent loops before transitioning to forwarding. PortFast bypasses these intermediate states, allowing the port to immediately enter forwarding mode, which reduces network convergence time and speeds up device connectivity. The decision to enable PortFast is based on the port's role in the network topology. It should only be enabled on access ports connected to end devices, not on inter-switch links or trunk ports, because those links participate in STP topology calculations and need the standard delay to prevent loops. Cisco switches typically warn or disable PortFast on trunk ports to avoid misconfiguration. This selective application ensures rapid host connectivity without compromising network stability. A common exam trap is confusing PortFast with other STP-related features like Root Guard or Loop Guard, which serve different purposes such as protecting the root bridge or preventing loops due to unidirectional link failures. Misapplying PortFast on inter-switch links can cause network loops and instability. Understanding the practical behavior of PortFast and its intended use case helps avoid these pitfalls and supports proper access-layer design in Cisco networks.
KKey Concepts to Remember
- PortFast enables a switchport connected to an end device to immediately transition to forwarding state, bypassing the usual STP listening and learning delays.
- PortFast must only be enabled on access ports connected to end devices and never on inter-switch trunk links to prevent network loops.
- Spanning Tree Protocol uses listening and learning states to prevent loops, but PortFast skips these states on edge ports to speed up host connectivity.
- Root Guard protects the root bridge election process by blocking ports that receive superior BPDUs but does not affect port forwarding speed.
- Loop Guard prevents STP topology changes caused by unidirectional link failures but does not accelerate port forwarding on edge ports.
- UDLD aggressive mode detects unidirectional link failures on fiber links and does not influence STP port states or forwarding delays.
- Cisco switches typically warn or disable PortFast on trunk ports to prevent misconfiguration and potential network loops.
- Proper use of PortFast improves network convergence time for end devices without compromising STP stability on inter-switch links.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
PortFast enables a switchport connected to an end device to immediately transition to forwarding state, bypassing the usual STP listening and learning delays.
What is the correct answer to this question?
The correct answer is: PortFast — PortFast is intended for that exact edge-port behavior. In plain language, it lets a host-facing access port skip the usual long listening and learning delay and move to forwarding much faster, which helps PCs and similar devices come online without waiting unnecessarily. At the same time, it is not meant for normal inter-switch links because those links participate more fully in spanning-tree calculations and need to be treated more carefully. This is a classic access-layer design concept. The correct answer is the feature built specifically for end-host edge ports rather than for trunk protection or routed-port operation.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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