Which are valid modes for a switch port used as a VLAN trunk? （）

单项选择题What is one benefit of PVST+?（）

A.PVST+reduces the CPU cycles for all the switches in the network
B.PVST+automatically selects the root bridge location,to provide optimized bandwidth usage.
C.PVST+allow the root switch location to be optimized per vlan.
D.PVST+supports Layer 3 load balancing without loops.

单项选择题Refer to the exhibit. What switch proves the spanning-tree designated port role for the network segment that services the printers?（）

A.Switch1
B.Switch2
C.Switch3
D.Switch4

单项选择题Refer to the exhibit.The network administrator normally establishes a telnet session with the switch from host A.However,host A is unavailable.The administrator′s attempt to the switch from host B fails,but pings to the other two hosts are successful.what is the issue?（）

A.Host B and the switch need to be in the same subnet.
B.The switch needs and appropriate default gateway assigned.
C.The switch interface connected to the router is down.
D.Host B need to be assigned an IP address in vlan 1.
E.The switch interfaces need the appropriate IP addresses assigned.

多项选择题Which two of these are characteristics of the 802.1Q protocol?（）

A.it is a layer 2 messaging protocol which maintains vlan configurations across network.
B.it includes an 8-bit field which specifies the priority of a frame.
C.it is used exclusively for tagging vlan frames and dose not address network reconvergence following switched network topology changes.
D.it modifies the 802.3 frame header,and thus requires that the FCS be recomputed.
E.it is a trunking protocol capable of carring untagged frames.

单项选择题Based on the network shown in the graphic which option contains the potential networking problem and protocol or setting that can to prevent the problem?（）

A.Routing loops, hold down timers
B.Switching loops, split horizon
C.Routing loops, split horizon
D.Switching loops, VTP
E.Routing loops, STP
F.Switching loops, STP