The correct answer is that the peer-link carries all VLANs allowed on the trunk interface, not just those configured on member ports. This is because the vPC peer-link must maintain a complete Layer 2 topology between the two peers, ensuring that any broadcast, multicast, or unknown unicast frame—including orphaned traffic arriving from a downstream device—can be forwarded across the link without relying on Spanning Tree Protocol to block loops. On the Cisco DCCOR 350-601 exam, this concept often appears as a trick question where candidates mistakenly think the peer-link only carries VLANs active on vPC member ports, but the truth is that the peer-link must carry every VLAN permitted on the trunk to preserve loop-free forwarding and handle traffic for non-vPC devices. A solid memory tip is: “Peer-link is the highway for all allowed VLANs, not just the ones with on-ramps.”
350-601 Network Practice Question
This 350-601 practice question tests your understanding of network. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which statement is true about the VLANs carried on a VPC peer-link?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The peer-link carries all VLANs that are allowed on the trunk interface.
In a vPC domain, the peer-link is a special trunk that carries all VLANs allowed on the trunk interface, including those not present on any member port. This ensures that orphaned traffic (traffic arriving on the peer-link destined for a device connected to the other vPC peer) can be forwarded correctly. The peer-link must carry all VLANs to maintain Layer 2 connectivity and loop-free behavior without relying on spanning tree.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The peer-link carries only the VLANs allowed on the member interfaces.
Why it's wrong here
The peer-link's allowed VLANs are configured separately.
✓
The peer-link carries all VLANs that are allowed on the trunk interface.
Why this is correct
The peer-link is a trunk that can carry any VLAN allowed on it.
Related concept
Read the scenario before looking for a memorised answer.
✗
The peer-link requires spanning-tree port type edge trunk configuration.
Why it's wrong here
This is optional, not required.
✗
The peer-link must be configured as a layer 3 interface.
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that the peer-link only carries VLANs present on member ports, when in fact it must carry all VLANs allowed on the trunk to support orphan port traffic and maintain vPC loop-free operation.
Detailed technical explanation
How to think about this question
The vPC peer-link uses a special Cisco-proprietary mechanism where the two peers synchronize MAC addresses and ARP entries via the CFS (Cisco Fabric Services) protocol over the peer-link. The peer-link must be configured as a trunk and should include all VLANs that could potentially be used by orphan ports or vPC member ports to avoid traffic black-holing. In real-world designs, failing to allow a VLAN on the peer-link can cause asymmetric routing or packet drops for traffic that arrives on one peer but must exit via the other peer's orphan port.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Network — This question tests Network — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The peer-link carries all VLANs that are allowed on the trunk interface. — In a vPC domain, the peer-link is a special trunk that carries all VLANs allowed on the trunk interface, including those not present on any member port. This ensures that orphaned traffic (traffic arriving on the peer-link destined for a device connected to the other vPC peer) can be forwarded correctly. The peer-link must carry all VLANs to maintain Layer 2 connectivity and loop-free behavior without relying on spanning tree.
What should I do if I get this 350-601 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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