Which two of these statements regarding RSTP are correct? （）
第1题：
A. Features such as UplinkFast and BackboneFast are compatible with RSTP.
B. An RSTP that is based on Cisco products generally performs better than the Cisco proprietary 802.1D enhancements.
C. Cisco proprietary enhancements are not transparent.
D. Information about port roles is sent to all switches.
E. RSTPs that are based on Cisco products require no additional configuration.
第2题：
A. RSTP significantly reduces topology reconverging time after a link failure.
B. RSTP expends the STP port roles by adding the alternate and backup roles.
C. RSTP port atates are blocking,discarding,learing,or forwarding.
D. RSTP also uses the STP proprsal-agreement sequence.
E. RSTP use the same timer-baseed process as STP on point-to-point links.
F. RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.
第3题：
A.第2层网络拓扑发生变化时，需要重新计算生成树，而RSTP提高了这种计算的速度
B.RSTP是一种IEEE标准，重新定义了STP端口角色、端口状态和BPDU
C.RSTP极具前瞻性且反应迅速，因此绝对需要802.1d的延迟定时器
D.RSTP( 802.1w)优于802.1d，但依然是专用的
E.RSTP修改了所有802.1d术语和大部分参数
F.为支持传统交换机，可在每个端口上进行配置，让802.1w退化为802.1d
第4题：
A.RSTP和STP不可互操作，会进行独立运算
B.RSTP可以和STP互操作，但是此时会丧失快速收敛等RSTP优势
C.如果是华为交换设备，则RSTP会转换到STP模式，并且可以配置运行STP的交换设备被撤离网络后，运行RSTP的交换设备可迁移回到RSTP工作模式
D.如果是华为交换设备，则STP会转换到RSTP模式，并且可以配置运行RSTP的交换设备被撤离网络后，运行STP的交换设备可迁移回到RSTP工作模式
第5题：
A.RSTP无法与PVST+操作
B.RSTP定义新端口角色
C.RSTP没有定义新的端口状态
D.RSTP是一个专有的执行IEEE802.1D生成树协议
E.RSTP与原来的IEEE802.1DSTP兼容
第6题：
A.blocking
B.learning
C.disabled
D.forwarding
E.listening
第7题：
A. RSTP cannot operate with PVST+.
B. RSTP defines new port roles.
C. RSTP defines no new port states.
D. RSTP is a proprietary implementation of IEEE 802.1D STP.
E. RSTP is compatible with the original IEEE 802.1D STP.
第8题：
A. Features such as UplinkFast and BackboneFast are compatible with RSTP.
B. An RSTP that is based on Cisco products generally performs better than the Cisco proprietary 802.1D enhancements.
C. Cisco proprietary enhancements are not transparent.
D. Information about port roles is sent to all switches.
E. RSTPs that are based on Cisco products require no additional configuration.
第9题：
A.RSTP significantly reduces topology reconverging time after a link failure.
B.RSTP expends the STP port roles by adding the alternate and backup roles.
C.RSTP portatates are blocking,discarding,learing,orforwarding.
D.RSTP also uses the STP proprsal-agreement sequence.
E.RSTP use the same timer-baseed process as STP on point-to-point links.
F.RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.
第10题：
avoid Layer 2 loops. Which two of the following are most probably the reasons for that preference?（）