单项选择题 The Testking network is implementing dialup services for their remote employees.Testking uses several different Layer 3 protocols on the network. Authentication ofthe users connecting to the network is required for security. Additionally, some employees will be dialing long distance and will need callback support.Which protocol is the best choice for these remote access services?（）

多项选择题 Which dynamic routing protocol should be recommended for the Testking networkshown in the graphic above?（）

多项选择题 A brand new network application is required for the Acme Company, and they are considering the use of a connectionless service. What are the characteristics of a connectionless service?（）