多项选择题
Which of the following are types of flow control? (Choose three.)（）
A.buffering B.cut-through C.windowing D.congestion avoidance E.load balancing
单项选择题 Acknowledgements,sequencing,andflowcontrolarecharacteristicsofwhichOSIlayer?（）
单项选择题 WhenanewtrunklinkisconfiguredonanIOSbasedswitch,whichVLANsareallowedoverthelink?（）
单项选择题 WhenarouterisconnectedtoaFrameRelayWANlinkusingaserialDTEinterface,howistheinterfaceclockratedetermined?（）
