A.added securityB.dedicated bandwidthC.provides segment……

单项选择题Refer to the exhibit. Which statement is true?（）

A.The Fa0/11 role confirms that SwitchA is the root bridge for VLAN 20.
B.VLAN 20 is running the Per VLAN Spanning Tree Protocol.
C.The MAC address of the root bridge is 0017.596d.1580.
D.SwitchA is not the root bridge, because not all of the interface roles are designated.

单项选择题What dose a Layer 2 switch use to decide where to forward a received frame?（）

A.source MAC address
B.source IP address
C.source switch port
D.destination IP address
E.destination port address
F.destination MAC address

单项选择题At which layer of the OSI model is RSTP used to prevent loops?（）

A.data link
B.network
C.physical
D.transport

多项选择题Which three statements about RSTP are true?（）

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 satates 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.

单项选择题Refer to the exhibit A frame on vlan 1 on switch s1 is sent to switch s2 when the frame is received on vlan 2,what causes this behavior?（）

A.trunk mode mismatches
B.vlans that do not correspond to a unique IP subnet
C.native vlan mismatches
D.allowing only vlan 2 on the destination.