单项选择题
A.core layer
B.Internet boundary
C.aggregation layer
D.aggregation and core layers
E.access and aggregation layers
多项选择题 WhichtwoofthesearecharacteristicsofanIDSsensor？（）
多项选择题 Users of a site-to-site VPN are reporting performance problems. The VPN connection employs IPSec and GRE and traverses several Ethernet segments. The VPN packets are being fragmented as they traverse the links. What would be two methods to overcome this problem?（）
单项选择题 Whichofthesetermsreferstocallissuesthatcausevariationsintimingortimeofarrival？（）