Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Exhibit
SW1# show vlan brief 60 Users-60 active SW2# show vlan brief 10 Users-10 active 20 Users-20 active SW2# show interfaces trunk Port Mode Encapsulation Status Native vlan Gi0/1 on 802.1q trunking 1 Port Vlans allowed on trunk Gi0/1 10,20,60
Based on the exhibit, what is the most likely reason users in VLAN 60 on SW2 cannot reach the default gateway on SW1?
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
VLAN 60 does not exist locally on SW2.
This is correct because trunk allowance alone is not enough if the VLAN is missing from the local switch.
B
Distractor review
The native VLAN must be changed to 60 on both switches.
This is wrong because the issue is local VLAN existence, not native VLAN choice.
C
Distractor review
VLAN 60 can be used only if PPP is enabled on the trunk.
This is wrong because PPP is unrelated to 802.1Q VLAN forwarding.
D
Distractor review
The default gateway must be configured as a loopback on SW2.
This is wrong because the problem is VLAN handling, not loopback gateway design.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is assuming that allowing a VLAN on a trunk link is sufficient for connectivity. Candidates may focus on trunk configuration details like native VLAN mismatches or encapsulation protocols, ignoring the fundamental requirement that the VLAN must exist locally on each switch. This mistake leads to selecting incorrect answers related to native VLAN changes or unrelated protocols like PPP. The key trap is forgetting that VLANs must be created and active on all switches participating in that VLAN, or else traffic will be dropped even if trunks are properly configured.
Technical deep dive
How to think about this question
VLANs (Virtual Local Area Networks) segment a physical network into multiple logical broadcast domains, allowing devices to communicate as if they were on separate physical networks. Each VLAN must be explicitly created on a switch to define its broadcast domain and associated Layer 2 forwarding behavior. When a switch receives traffic tagged with a VLAN ID, it forwards the frame only if that VLAN exists locally; otherwise, the traffic is dropped or ignored. In Cisco switching environments, trunk links carry multiple VLANs between switches using 802.1Q tagging. However, simply allowing a VLAN on a trunk does not guarantee connectivity. The VLAN must be configured and active on both ends of the trunk. If a VLAN is missing on a switch, access ports assigned to that VLAN cannot forward traffic properly, and devices in that VLAN cannot reach their default gateway or other network resources. The exam trap here is focusing solely on trunk configuration and native VLAN settings while overlooking the necessity of local VLAN creation. Even if the trunk allows VLAN 60, if SW2 does not have VLAN 60 defined, devices assigned to VLAN 60 on SW2 cannot communicate beyond their local switch. This practical issue often arises in campus networks where VLAN databases are not synchronized, causing connectivity failures despite correct trunk configurations.
KKey Concepts to Remember
- A VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN.
- Trunk links carry multiple VLANs using 802.1Q tagging but do not create VLANs on switches automatically.
- Access ports assign devices to VLANs that must exist locally on the switch to forward traffic correctly.
- If a VLAN is missing on a switch, traffic tagged for that VLAN is dropped or ignored on that switch.
- Native VLAN mismatches affect untagged traffic but do not replace the need for VLAN creation on each switch.
- PPP is unrelated to VLAN forwarding and does not affect 802.1Q trunk VLAN traffic.
- Default gateways for VLANs are typically configured on Layer 3 devices or SVIs, not as loopbacks on access switches.
- Network engineers must synchronize VLAN databases across switches to ensure consistent VLAN forwarding and connectivity.
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?
A VLAN must be explicitly created and active on a switch for that switch to forward traffic within that VLAN.
What is the correct answer to this question?
The correct answer is: VLAN 60 does not exist locally on SW2. — The most likely reason is that VLAN 60 has not been created on SW2 even though the trunk can carry it. In practical terms, allowing a VLAN on a trunk is not enough by itself. The receiving switch still needs the VLAN to exist locally so access ports can place traffic into that broadcast domain correctly. This is a realistic campus-switching problem because engineers sometimes focus only on the trunk and forget the local VLAN database on one side.
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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