题目内容：
A.Classificationandmarkingoccurusing802.1abQoSbitsbeforereachingthetrustboundary.
B.Adeviceistrustedifitcorrectlydeclassifiespackets.
C.Adeviceistrustedifitcorrectlyclassifiespackets.
D.NetworktrustboundariesareautomaticallyconfiguredinIOSversion12.3andlater.
E.Theoutermosttrusteddevicesrepresentthetrustboundary.
F.Forscalability，classificationshouldbedoneasclosetotheedgeaspossible.
参考答案：