Refer to the exhibit.
Why does the trust state of interface FastEthernet 0/3 show “not trusted”?
A.
DSCP map needs to be configured for VOIP.
B.
ToS has not been configured.
C.
ToS has been misconfigured.
D.
The command mls qos needs to be turned on in global configuration mode.
E.
There is not a Cisco Phone attached to the interface.
Explanation:
CDP is a device discovery protocol that runs over Layer 2 (the data link layer) on all Ciscomanufactured devices (routers, bridges, access servers, and switches) and allows network
management applications to discover Cisco devices that are neighbors of already known
devices. With CDP, network management applications can learn the device type and the
Simple Network Management Protocol (SNMP) agent address of neighboring devices
running lower-layer, transparent protocols. This feature enables applications to send SNMP
queries to neighboring devices.
CDP runs on all media that support Subnetwork Access Protocol (SNAP). Because CDP
runs over the data-link layer only, two systems that support different network-layer protocols
can learn about each other.
Communication between Switch and IP Phone is performed by CDP protocol. There is no
CDP neighbor and trusted state also no trusted.