CCNP系列認(rèn)證CCNP(642-813)單項(xiàng)選擇題每日一練(2019.01.22)

On switch R1 you issue the "udld enable" global command. 
What does this command accomplish？ （）

Refer to the exhibit. 
What is the effect on the trust boundary of configuring the command mls qos  trust cos on the switch port that is connected to the IP phone？（）

Three Cisco Catalyst switches have been configured with a first-hop redundancy protocol. While reviewing some show commands， debug output， and the syslog， you discover the following information：

What conclusion can you infer from this information？（）

Two Company switches are connected via a trunk link. In this network， the original frame is  encapsulated and an additional header is added before the frame is carried over a trunk link. At  the receiving end， the header is removed and the frame is forwarded to the assigned VLAN. 
This  describes which technology？（）