You are the Cisco Network Designer in Cisco.com. Which statement is correct regarding NBAR and NetFlow?（）

单项选择题Whichsite-to-siteVPNsolutionallowsCiscorouters，PIXFirewalls，andCiscohardwareclientstoactasremoteVPNclientsinordertoreceivepredefinedsecuritypoliciesandconfigurationparametersfromtheVPNheadendatthecentralsite？（）

A.Easy VPN
B.GRE tunneling
C.Virtual Tunnel Interfaces
D.Dynamic Multipoint VPN
E.Group Encrypted Transport VPN

单项选择题WhyisSTPrequiredwhenVLANsspanaccesslayerswitches？（）

A.to ensure a loop-free topology
B.to protect against user-side loops
C.in order to support business applications
D.because of the risk of lost connectivity without STP
E.for the most deterministic and highly available network topology

单项选择题InaVoWLANdeployment，whatistherecommendedseparationbetweencellswiththesamechannel？（）

A.19 dBm
B.7 dBm
C.10 dBm
D.6 dBm
E.5 dbm to 10 dBm

单项选择题Whatisavirtualfirewall？（）

A.another name for a firewall deployed in routed mode
B.another name for a firewall deployed in transparent mode
C.a separation of multiple firewall security contexts on a single firewall
D.a firewall that， when deployed in routed mode， can support up to 1000 VLANs per context
E.a firewall that has multiple contexts， all of which share the same policies （such as NAT and ACLs）

多项选择题InwhichtwolocationsinanenterprisenetworkcananIPSsensorbeplaced？（）

A.bridging VLANs on two switches
B.bridging two VLANs on one switch
C.between two Layer 2 devices with trunking
D.between two Layer 2 devices without trunking
E.between a Layer 2 device and a Layer 3 device with trunking