Which configuration tells a switch port to send Cisco Discovery protocol packets that configure an attached Cisco IP phone to trust tagged traffic that is received from a device that is connected to…

The command 'switchport voice vlan trust' is the key part of the configuration that enables a Cisco switch port to signal a connected IP phone via CDP to trust tagged traffic received on the phone's access port. This ensures that a device connected to the PC port of the IP phone (e.g., a computer) can send traffic with QoS markings (like 802.1p CoS) that the IP phone will honor and pass through to the switch.

If this refers to 'mls qos trust cos' or 'mls qos trust dscp' without 'switchport voice vlan trust', it configures the *switch* to trust CoS/DSCP, but not the *phone* to trust the connected *device*.

If this refers to an H.323 configuration, it is irrelevant for configuring an IP phone's trust settings on a switch port.

If this refers to 'trust device cisco-phone', this command is usually part of 'auto qos voip trust' and is more about the switch auto-configuring QoS for the phone, not specifically the CDP message to the phone about trusting its access port. The 'switchport voice vlan trust' explicitly tells the phone to trust.