单项选择题
A.after broken links are re-established
B.in an improperly implemented redundant topology
C.when upper-layer protocols require high reliability
D.during high traffic periods
E.when a dual ring topology is in use
多项选择题 Which router IOS commands can be used to troubleshoot LAN connectivity problems?（）
单项选择题 Refer to the exibit .An attempt to deny web access to a subnet blocks all traffic from the subnet.Which interface command immedicately removes the effect of ACL 102?（）
单项选择题 What will happen if a private IP address is assigned to a public interface connected to an ISP?（）