层状介质情况下，引入平均速度的条件是什么？
Which mechanism can you use to achieve sub-second failover for link failure detection when a switched Ethernet media is used and loss of signal is not supported by the link provider？（） ["OSPF standard hellos","Cisco Discovery Protocol link detection","Bidirectional Forwarding Detection","Fast Link Pulse","autonegotiatio"]
Which three statements about the Cisco MPLS TE Fast Reroute （FRR） process are true？（） ["TE tunnels that are configured with the FRR option cannot be used as backup tunnels.","TE tunnels that are configured with the FRR option can be used as backup tunnels.","The backup tunnel that is used to protect a physical interface must have a valid IP address configured.","Interfaces must use MPLS global label allocation.","The source IP address of use backup tunnel and the merge point （MP） should not be reachable."]
在主信道上进行测试时，一般需要对哪些指标进行测试（） ["MRI-R点的光功率指标","MPI-R点的OSNR","MPI-S点的总输出功率","收端主信道的光谱特性"]
因为企业的价值与预期的报酬成正比，与预期的风险成反比，因此企业的价值只有在报酬最大风险最小时才能达到最大。（）
抽样调查
