单项选择题 Which spread spectrum technology does the 802.11b standard define for operation?（）

单项选择题 A cisco router is booting and has just completed the POST process.It is now ready to find and load an IOSimage.what function does the router perform next?（）

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?（）