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?（）
 

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

单项选择题Which command can be used from a PC to verify the connectivity between hosts that connect through a switch in the same LAN?（）

A.ping address
B.tracert address
C.traceroute address
D.arp address

多项选择题Which two benefits are provided by creating VLANs? （）

A.added security
B.dedicated bandwidth
C.provides segmentation
D.allows switches to route traffic between subinterfaces
E.contains collisions

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.