200-301: Cisco Certified Network AssociateDemo

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QuestionQ52

Network Access

A Cisco engineer must configure a single switch interface to meet these requirements:

  • Accept untagged frames and place them in VLAN 20
  • Accept tagged frames in VLAN 30 when CDP detects a Cisco IP phone

Question Image

Which command set should the engineer apply?

  • A switchport mode dynamic desirable switchport access vlan 20 switchport trunk allowed vlan 30 switchport voice vlan 30
  • B switchport mode access switchport access vlan 20 switchport voice vlan 30
  • C switchport mode dynamic auto switchport trunk native vlan 20 switchport trunk allowed vlan 30 switchport voice vlan 30
  • D switchport mode trunk switchport access vlan 20 switchport voice vlan 30
Explanation

A Cisco switch port that connects to an IP phone with a downstream PC is normally configured as an access port for the data VLAN and a voice VLAN for the phone. switchport mode access makes the interface a nontrunking access port, switchport access vlan 20 places untagged traffic in VLAN 20, and switchport voice vlan 30 tells a Cisco IP phone through CDP to use VLAN 30 for tagged voice traffic. That exactly matches the requirement of untagged data in VLAN 20 and tagged phone traffic in VLAN 30.

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