CCNA Switching and Network Access Practice Question
A multilayer switch has SVIs for VLAN 10 and VLAN 20. Hosts in both VLANs can reach their local SVI, but they cannot reach each other. Which additional configuration is most likely required?
⚠ Common exam trap
Don't assume SVIs automatically enable inter-VLAN routing; IP routing must be explicitly enabled.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable `ip routing` on the multilayer switch.
The most likely missing configuration is `ip routing`. In practical terms, the switch already has Layer 3 gateway interfaces for the VLANs, which is why hosts can reach their local SVI. But inter-VLAN communication still requires the switch to actually route between those VLAN interfaces. Without IP routing enabled, the SVIs can exist and respond locally without forwarding traffic between them. This is a classic multilayer-switch question because many learners assume that creating SVIs automatically enables inter-VLAN routing. It does not. The device must also be told to behave as a Layer 3 forwarding device across those VLAN interfaces.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Enable `ip routing` on the multilayer switch.
Why this is correct
Without `ip routing`, the switch enforces its default behavior as a Layer 2 device: the SVIs exist with IP addresses but no dynamic or static route is installed to move packets between VLANs. Entering `ip routing` enables the Layer 3 forwarding engine (CEF) and makes the SVIs act as routed gateway interfaces. This is the exact missing command for inter-VLAN forwarding on a multilayer switch.
- ✗
Convert all access ports into trunks.
Why it's wrong here
Host-facing ports should remain access ports carrying a single untagged VLAN; trunks are designed for switch-to-switch or switch-to-router links that multiplex many VLANs over one link. Converting all access ports into trunks would require end hosts to use 802.1Q tagging, which typical PC NICs do not support, and it does not address the lack of Layer 3 routing. This change would disrupt connectivity without doing anything to enable inter-SVI forwarding.
When this WOULD be correct
In a scenario where the question specifies that hosts in VLAN 10 and VLAN 20 are connected to access ports and need to communicate with devices in another VLAN that is only reachable via trunk links, converting access ports to trunks would be necessary to allow VLAN tagging and proper routing.
- ✗
Make both VLANs use the same IP subnet.
Why it's wrong here
Assigning both VLANs the same IP subnet would make the IP address ranges overlap on the two SVIs, causing ambiguous routes and invalid ARP resolution between the switch and hosts. Each SVI must be on a unique subnet to act as a separate default gateway and for the routing table to distinguish the networks. The VLANs must remain as distinct Layer 2 broadcast domains with distinct IP networks for routing to work.
When this WOULD be correct
In a different scenario where the question states that both VLANs need to communicate but are assigned to the same subnet due to a misconfiguration, then making both VLANs use the same IP subnet would be necessary to allow inter-VLAN communication.
- ✗
Disable spanning tree on both VLANs.
Why it's wrong here
Spanning Tree Protocol operates at Layer 2 to prevent loops in a redundant switched topology and has no part in routing decisions between SVIs. Disabling STP on VLAN 10 and 20 would not create a route or enable CEF, so inter-VLAN traffic would still be dropped at the switch. It would also expose the network to broadcast storms and MAC flapping.
When this WOULD be correct
In a different scenario where a question states that VLANs are experiencing excessive broadcast traffic and network loops, and the requirement is to optimize the network by removing spanning tree protocol, then disabling spanning tree could be the correct answer.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Enable `ip routing` on the multilayer switch.Correct answer▾
Why this is correct
Without `ip routing`, the switch enforces its default behavior as a Layer 2 device: the SVIs exist with IP addresses but no dynamic or static route is installed to move packets between VLANs. Entering `ip routing` enables the Layer 3 forwarding engine (CEF) and makes the SVIs act as routed gateway interfaces. This is the exact missing command for inter-VLAN forwarding on a multilayer switch.
✗Convert all access ports into trunks.Wrong answer — click to see why▾
Why this is wrong here
Converting all access ports to trunks is unnecessary and incorrect because host-facing ports should remain access ports assigned to a single VLAN. Trunks are used to carry multiple VLANs between switches, not to connect end hosts. This change would not enable inter-VLAN routing.
★ When this WOULD be the correct answer
In a scenario where the question specifies that hosts in VLAN 10 and VLAN 20 are connected to access ports and need to communicate with devices in another VLAN that is only reachable via trunk links, converting access ports to trunks would be necessary to allow VLAN tagging and proper routing.
Why candidates choose this
A student might think that trunks are needed to carry traffic between VLANs, but inter-VLAN routing is a Layer 3 function, not a Layer 2 trunking issue. The confusion arises from mixing the concepts of VLAN trunking and routing.
✗Make both VLANs use the same IP subnet.Wrong answer — click to see why▾
Why this is wrong here
Making both VLANs use the same IP subnet would break the fundamental purpose of VLANs, which is to separate broadcast domains and logically segment the network. Hosts in different VLANs must be in different subnets for proper routing; otherwise, they would expect to communicate directly at Layer 2, which is not possible across VLANs.
★ When this WOULD be the correct answer
In a different scenario where the question states that both VLANs need to communicate but are assigned to the same subnet due to a misconfiguration, then making both VLANs use the same IP subnet would be necessary to allow inter-VLAN communication.
Why candidates choose this
A student might think that using the same subnet would allow hosts to communicate directly, but this ignores that VLANs are separate broadcast domains. Even with the same subnet, hosts in different VLANs cannot communicate without a router, and the switch would not forward frames between VLANs at Layer 2.
✗Disable spanning tree on both VLANs.Wrong answer — click to see why▾
Why this is wrong here
Disabling Spanning Tree Protocol (STP) on both VLANs would not enable inter-VLAN routing; it would only risk creating Layer 2 loops and broadcast storms. STP is a loop-prevention mechanism and has no role in Layer 3 routing between VLANs.
★ When this WOULD be the correct answer
In a different scenario where a question states that VLANs are experiencing excessive broadcast traffic and network loops, and the requirement is to optimize the network by removing spanning tree protocol, then disabling spanning tree could be the correct answer.
Why candidates choose this
A student might incorrectly associate STP with blocking traffic and think that disabling it would allow traffic to flow freely. However, STP does not block inter-VLAN traffic; it only prevents loops in redundant topologies. The real issue is the lack of IP routing.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
Go deeper
Related to this question
Learn chapter
Configuring Switch Ports for Desktops, VoIP Phones, APs, IoT, and Virtualized Hosts
Key term
Switch Virtual Interface
A logical interface on a network switch that allows it to be managed and communicate with other devices using IP addresses.
Key term
Inter-VLAN routing
Inter-VLAN routing is the process of forwarding network traffic between different VLANs to enable communication across logically separated broadcast domains.
About these practice questions
One of 1,389 original 200-301 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.