单项选择题
A. It checks the configuration register
B. It attempts to boot from a TFTP server
C. It loads the first image file in flash memory
D. It inspects the configuration file in NVRAM for boot instructions
单项选择题 Router A is unable to reach Router B.Both routers are running ios version 12.0.After reviewing the command output and graphic,what is the most likely cause of the problem?（）
单项选择题 Which command enables IPv6 forwarding on a cisco router?（）
单项选择题 In the implementation of VLSM techniques on a network using a single Class C IP address,which subnet mask is the most efficient for point-to-point serial links?（）