CCNA Switching and Network Access Practice Question
Exhibit
MLS1#show running-config interface FastEthernet0/1 Building configuration... Current configuration : 93 bytes ! interface FastEthernet0/1 no switchport ip address 192.168.10.1 255.255.255.0 duplex auto speed auto !
You are connected to a multilayer switch MLS1. Configure FastEthernet0/1 as an access port for an IP phone and a PC, with voice VLAN 20 and data VLAN 10. Also enable PoE on the port. Then verify the configuration using 'show interfaces switchport' and 'show power inline'.
⚠ Common exam trap
The trap is that candidates may incorrectly use 'no switchport' to make the interface a routed port, or use trunk mode instead of access mode with voice VLAN. Remember that for end devices, the port must be an access port; the voice VLAN is configured separately. Also, ensure PoE is enabled with 'auto', not 'never'.
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
✓
interface FastEthernet0/1 switchport mode access switchport access vlan 10 switchport voice vlan 20 power inline auto no shutdown
It configures FastEthernet0/1 as an access port with data VLAN 10, voice VLAN 20, and PoE enabled, which is the required setup for an IP phone and PC. Option B is incorrect because 'no switchport' makes the interface a routed port (Layer 3), but it needs to be a Layer 2 access port to support an IP phone and PC. Option C is incorrect because trunk mode is used for switch-to-switch links, not for connecting end devices like an IP phone and PC. Option D is incorrect because 'power inline never' disables PoE, but the IP phone requires power; it should use 'power inline auto'.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
interface FastEthernet0/1 switchport mode access switchport access vlan 10 switchport voice vlan 20 power inline auto no shutdown
Why this is correct
This configuration correctly sets the interface as an access port, assigns data VLAN 10 for the PC and voice VLAN 20 for the IP phone via Cisco's voice VLAN feature. The 'power inline auto' command enables PoE to supply power to the phone, and 'no shutdown' ensures the port is administratively up. The use of 'switchport mode access' combined with a separate voice VLAN allows both devices on a single physical link while keeping traffic separated.
- ✗
interface FastEthernet0/1 no switchport ip address 192.168.1.1 255.255.255.0 power inline auto no shutdown
Why it's wrong here
The 'no switchport' command converts the Layer 2 switchport into a routed port, which operates at Layer 3 and cannot carry VLAN-specific traffic for an IP phone and PC. Since an IP phone and PC require VLAN tagging (data and voice VLANs), this configuration is invalid. The IP address is unnecessary and would render the port unable to connect to the VLANs, and the phone wouldn't receive proper untagged or tagged traffic.
- ✗
interface FastEthernet0/1 switchport mode trunk switchport trunk allowed vlan 10,20 power inline auto no shutdown
Why it's wrong here
A trunk port is designed to carry multiple VLANs between switches, not to connect end devices like an IP phone and PC. The 'switchport mode trunk' command would expect 802.1Q tags on all frames, but a PC typically sends untagged frames, and the phone would need to be configured to tag its voice VLAN while the PC's untagged traffic would not be assigned to the data VLAN correctly. Access mode with a separate voice VLAN is the correct approach.
- ✗
interface FastEthernet0/1 switchport mode access switchport access vlan 10 switchport voice vlan 20 power inline never no shutdown
Why it's wrong here
The 'power inline never' command explicitly disables Power over Ethernet on the port, which would prevent the IP phone from receiving power. Even though the VLAN configuration is correct, without power the phone cannot boot or function. The correct command is 'power inline auto' to enable PoE if the device requests it.
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.
✓interface FastEthernet0/1 switchport mode access switchport access vlan 10 switchport voice vlan 20 power inline auto no shutdownCorrect answer▾
Why this is correct
This configuration correctly sets the interface as an access port, assigns data VLAN 10 for the PC and voice VLAN 20 for the IP phone via Cisco's voice VLAN feature. The 'power inline auto' command enables PoE to supply power to the phone, and 'no shutdown' ensures the port is administratively up. The use of 'switchport mode access' combined with a separate voice VLAN allows both devices on a single physical link while keeping traffic separated.
✗interface FastEthernet0/1 no switchport ip address 192.168.1.1 255.255.255.0 power inline auto no shutdownWrong answer — click to see why▾
Why this is wrong here
The specific factual error: 'no switchport' disables Layer 2 switching on the interface, preventing VLAN assignment and the use of voice VLAN.
Why candidates choose this
Candidates might think a routed port is needed for the phone or that an IP address must be assigned to the interface.
✗interface FastEthernet0/1 switchport mode trunk switchport trunk allowed vlan 10,20 power inline auto no shutdownWrong answer — click to see why▾
Why this is wrong here
The specific factual error: trunk mode is inappropriate for an end-user port; it would expect VLAN tagging from the connected device, which PCs and phones do not typically provide.
Why candidates choose this
Candidates may confuse trunking with the ability to carry voice and data VLANs, not realizing that the switch uses the voice VLAN feature on an access port.
✗interface FastEthernet0/1 switchport mode access switchport access vlan 10 switchport voice vlan 20 power inline never no shutdownWrong answer — click to see why▾
Why this is wrong here
The specific factual error: 'power inline never' explicitly disables power delivery, so the phone will not receive power.
Why candidates choose this
Candidates might think 'never' is a valid option to conserve power or misunderstand the PoE configuration commands.
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?”
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Related to this question
Learn chapter
Configuring Switch Ports for Desktops, VoIP Phones, APs, IoT, and Virtualized Hosts
Key term
Interface
An interface is a point of connection or interaction between two systems, devices, or software components that allows them to exchange information or signals.
Key term
Voice VLAN
A Voice VLAN is a separate virtual local area network configured on a network switch to carry voice traffic, such as from IP phones, ensuring quality of service and security by isolating it from data traffic.
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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.