单项选择题
A. Layer 2 TTL
B. Layer 3 TTL
C. Layer 3 source address
D. Layer 3 transport protocol
E. Layer 3 destination address
单项选择题 During which phase is a proposal developed and delivered?（）
单项选择题 When you enter the interface command auto qos voip cisco-phone on a port at the edge of a network, how does the Cisco Catalyst switch detect if a Cisco IP Phone is connected to the port? （）
单项选择题 Which switching engine enables the access control list lookup to be committed to hardware? （）