单项选择题
Which of the following does a star ring topology use for data transfer?（）
A.CSMA/CD B.CSMA/CA C.CHAP D.Token passing
单项选择题 Which of the following network hardware allows the MOST network traffic collisions?（）
单项选择题 In the OSI model, which of the following layers would be the cause of a session time-out while browsing the web?（）
