Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A network administrator is configuring an IEEE 802.1Q trunk between two switches. Which of the following must match on both ends for the trunk to function correctly?
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
The native VLAN ID
A mismatched native VLAN can cause traffic on the untagged VLAN to be placed in the wrong VLAN on the other switch.
B
Distractor review
The trunk port speed and duplex
Speed and duplex must match for any link, but this is not a trunk-specific requirement.
C
Distractor review
The encapsulation type
Both ends must use 802.1Q, but this is a standard setting and less likely to be misconfigured than the native VLAN.
D
Distractor review
The allowed VLAN list
The allowed VLAN list can be pruned differently on each end; the trunk will still pass traffic for VLANs allowed on both sides.
Common exam trap
Common exam trap: an active trunk can still block the VLAN you need
A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.
Technical deep dive
How to think about this question
VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.
KKey Concepts to Remember
- Access ports place end devices into a single VLAN.
- Trunk ports carry multiple VLANs between switches.
- Allowed VLAN lists decide which VLANs can cross a trunk.
- Native VLAN mismatch can create confusing symptoms.
TExam Day Tips
- Use show vlan brief to verify access VLANs.
- Use show interfaces trunk to verify trunk state and allowed VLANs.
- Do not treat every same-VLAN issue as a routing problem.
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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 network engineer needs to connect two switches located 400 meters apart. The cable run includes high electromagnetic interference from nearby machinery. The engineer decides to use fiber optic cabling. Which transceiver type and fiber combination should be used to ensure the link reaches 400 meters while remaining cost-effective?
Question 2
A network engineer is designing a new switched network and needs to ensure that broadcast traffic from one department does not reach another department's workstations. The engineer plans to use VLANs. Which of the following must be configured on the switches to isolate broadcast domains as intended?
Question 3
A security engineer is configuring a site-to-site VPN between two branch offices. The requirement is to encrypt all traffic between the two networks using IPsec. Which IPsec mode should be used to encrypt the entire IP packet including the original header?
Question 4
A network administrator is connecting two switches to increase bandwidth and provide redundancy. Which technology should be used to combine multiple physical links into a single logical link?
Question 5
A network administrator is experiencing issues where unauthorized devices are offering IP addresses to clients, causing connectivity problems. Which security feature should be enabled on switches to prevent this?
Question 6
A network administrator is troubleshooting a connectivity issue and suspects the problem is related to the physical cabling. At which layer of the OSI model should the administrator begin their investigation?
FAQ
Questions learners often ask
What does this N10-009 question test?
Access ports place end devices into a single VLAN.
What is the correct answer to this question?
The correct answer is: The native VLAN ID — For an 802.1Q trunk to operate properly, the native VLAN (by default VLAN 1) must be identical on both switches. Mismatched native VLANs can cause traffic to be incorrectly tagged or blocked. Speed and duplex should match, but that applies to any link, not specifically trunk. While encapsulation must be 802.1Q on both ends, the key configuration parameter that often causes issues is the native VLAN ID.
What should I do if I get this N10-009 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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