On a Cisco Catalyst Switch, which command is required to send CDP packets on a switch port that configures a Cisco IP phone to transmit voice traffic in 802.1Q frames, tagged with the voice VLAN ID 221?
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A. B. C. D.C.
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960/software/release/12-2_40_se/configuration/guide/scg/swvoip.pdfThe correct answer is C. Device(config-if)# switchport voice vlan 221.
Cisco Discovery Protocol (CDP) is a proprietary Layer 2 protocol that is used to share information about other directly connected Cisco equipment. Cisco IP phones use CDP to discover the switch port to which they are connected and the voice VLAN ID configured on the switch port.
When an IP phone is connected to a switch port, the switch port should be configured to carry both voice and data traffic. Typically, data traffic is carried on the native VLAN, while voice traffic is carried on a separate VLAN known as the voice VLAN.
To configure a switch port to transmit voice traffic in 802.1Q frames, tagged with the voice VLAN ID 221, the "switchport voice vlan" command needs to be used. The command syntax is as follows:
Device(config-if)# switchport voice vlan 221
This command configures the switch port to carry both data and voice traffic. It also sets the voice VLAN ID to 221. Note that this command only needs to be used on switch ports that are connected to Cisco IP phones.
Option A (Device(config-if)# switchport trunk allowed vlan 221) configures a switch port as a trunk port and allows VLAN 221 to be carried on the trunk. This command is not relevant for configuring a switch port for a Cisco IP phone.
Option B (Device(config-if)# switchport vlan voice 221) is an invalid command.
Option D (Device(config-if)# switchport access vlan 221) configures a switch port to belong to VLAN 221. This command is not relevant for configuring a switch port for a Cisco IP phone, since it does not allow both voice and data traffic to be carried on the same port.