Refer to the exhibit. Given the CPE deployment model, the Enterprise applications shown, and the functions being provided as designated, the appropriate product choice is（）.

单项选择题SelectakeybenefitofDSL.（）

A.TCP packet sizes can be optimized by the router so there is no IPSec or AAL5 padding.
B.The local loop is a dedicated connection for a single subscriber to the DSLAM. 
C.Access to the WAN media uses a poll/response mechanism so no two subscribers transmit at the same time. 
D.There are no distance requirements from the Central Office (CO). 

单项选择题Refer to the exhibit. Asymmetric broadband service with significantly greater downstream bandwidth is recommended for Teleworker deployment. Which reason is the most accurate?（）

A.Most ISPs do not provide QoS for residential broadband. Asymmetric bandwidth reduces the chance of downstream congestion when traffic from Internet sites competes for bandwidth with IP voice traffic.
B.Additional downstream bandwidth compensates for insufficient upstream bandwidth. The aggregate bandwidth provides the same result. 
C.The additional bandwidth is needed to access more than one site. Most HTTP traffic is downstream. 
D.The additional downstream bandwidth allows the Enterprise VPN device to send the IP voice packets much faster, allowing them to reach the Teleworker network with less latency.

单项选择题TheLAN-sideoftheTeleworkerrouterisassignedprivateIPaddressspace(RFC1918),andtheVPNtopologyisIPSec-only(noGREprotocol).WhenisitrequiredtoconfigureNAT pNATontheTeleworkerrouter?（）

A.when all access to the Internet is through the IPSec tunnel
B.when there is direct Internet access via split-tunneling
C.when there is no Internet access configured through the Teleworker router
D.whenever you have IOS-Firewall (CBAC) configured

单项选择题ChoosethetruestatementregardingQoSpre-classify.（）

A.QoS pre-classify permits making QoS decisions based on elements from the unencrypted IP packet.
B.QoS pre-classify is required when encrypting voice.
C.QoS pre-classify is an advantage to Service Providers transporting encrypted packets.
D.QoS pre-classify is not designed for IPSec/GRE configurations.

单项选择题WhenshouldyouenableNetworkAddressTranslationTransparency(NAT-T)ontheTeleworker?（）

A.when a router between the Teleworker router and the head-end VPN router is doing NAT/pNAT and does not support IPSec pass-through 
B.when the Teleworker router itself is doing NAT/pNAT
C.always
D.never