Which protocol is an open standard protocol framework that is commonly used in VPNs,to provid secure end-to-end communication?（）

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Which item represents the standard IP ACL?（）

A. access-list 50 deny 192.168.1.1 0.0.0.255
B. access-list 110 permit ip any any
C. access-list 2500 deny tcp any host 192.168.1.1 eq 22
D. access-list 101 deny tcp any host 192.168.1.1

单项选择题Which statement about access lists that are applied to an interface is true?（）

A. you can apply multiple access lists with the same protocol or in different direction.
B. you can config one access list,per direction,per layer 3 protocol
C. you can place as many access lists as you want on any interface
D. you can apply only one access list on any interface

单项选择题Which command enables RSTP on a switch?（）

A. spanning-tree mode rapid-pvst
B. spanning-tree uplinkfast
C. spanning-tree backbonefast
D. spanning-tree mode mst

单项选择题DNS servers provide what service?（）

A. they run a spell check on host names to ensure accurate routing
B. they map individual hosts to their specific IP address
C. they convert domain names into IP address
D. Given an IP address,they determine the name of the host that is…