Exam 200-301 topic 1 question 297 discussion

B should be the answer. With D, the interface operates in trunk mode. So the access configuration is not taken into account and the vlan 20 will be tagged.

My answer was C, this was chatGTP answer when I asked why it can't be C The command set in option C is not correct because it includes "switchport mode dynamic auto," which would cause the interface to become a trunk port if the neighboring device is set to trunk mode. In this scenario, the requirement is to accept untagged frames in VLAN 20 and tagged frames in VLAN 30 when a Cisco IP phone is detected. Therefore, the interface should be configured as an access port in VLAN 20 and a voice VLAN should be configured for VLAN 30. The command set that meets these requirements is option B: switchport mode access switchport access vlan 20 switchport voice vlan 30 Option A is incorrect because it sets the interface to dynamic desirable mode, which could result in the interface becoming a trunk port if the neighboring device is set to trunk or dynamic auto mode. It also allows VLAN 30 on the access port, which is not required. Option D is incorrect because it sets the interface to trunk mode, which is not necessary for this scenario.

This configuration uses an access port, which is a common and valid setup for connecting a Cisco IP phone with a PC behind it: Untagged frames (e.g., from the PC) are placed in VLAN 20 (access VLAN). Tagged frames from the IP phone, detected via CDP, are placed in VLAN 30 (voice VLAN). Cisco switches support this dual-VLAN capability on access ports when a voice VLAN is configured, making it the simplest and most reliable solution for the requirements.

Per Cisco documentation under the subtopic line Voice VLAN Configuration Guidelines, "Voice VLAN is only supported on access ports and not on trunk ports, even though the configuration is allowed. Quoted directly from the following source: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3560/software/release/12-2_44_se/configuration/guide/scg/swvoip.html#wp1033848

Only trunk ports support tagged and untagged frames simultaneously. Therefore, option C is the only correct answer.

I think it is B

B is correct, when you have voice and data, it needs to be an access port

B IS correct the phone's port is also a trunk port, this is not a great question also

A trunk port can not assign an access vlan

switchport mode access switchport access vlan 20 switchport voice vlan 30 Explanation: switchport mode access is used to set the switchport to access mode, which allows untagged frames to enter the VLAN specified by switchport access vlan 20. switchport access vlan 20 assigns untagged frames to VLAN 20. switchport voice vlan 30 configures the voice VLAN for Cisco IP phones. This command ensures that tagged frames detected by CDP from a Cisco IP phone will be placed in VLAN 30. Option B meets both of the specified requirements.

please the answer is B, its a true example of a ip phone.

Voice vlan works at access... No trunking for that port.

They want UNTAGGED VLAN -> access port

BBBBBBBB

wow a lot of these answers suck. cmon exam topics

answer B

untagged. so native vlan 20. native vlans allow frames to pass untagged