单项选择题
On the basis of the definitions of different services in various RFCs，traffic with Expedited Forwarding per-hop behavior should be marked as which of these？（）
A.IP ToS of 0xEF B.IP experimental ECN C.DSCP decimal 5 D.Binary value of 101110
单项选择题 WhichistheresultofenablingIPSourceGuardonanuntrustedswitchportthatdoesnothaveDHCPsnoopingenabled？（）
多项选择题 WhichthreestatementsaretrueaboutSourceSpecificMulticast？（）
问答题 vtppruneisnotdesignedforwhatmode？
