多选题Which two statements or sets of statements are true about the application of the qos pre-classify command？（）AIf the classification policy is based upon the ToS byte， the qos pre-classify command is required because the ToS byte only appears in the inne

第1题：

What does qos pre-classify provides inregardto implementing QoS over GRE/IPSec VPN tunnels？（）

• A、 enables IOS to copy the ToS field from the inner （original） IPheader to theouter tunnel IP header
• B、 enables IOS to make a copy of the inner （original） IP header and to run a QoS classification before encryption， based on fields in the inner IP header.
• C、 enables IOS to classify packets based on the ToS field in the inner （original） IP header
• D、 enables IOS to classify packets based on the ToS field in the outer tunnel IP header
• E、 enables the IOS classification engine to only see a single encrypted and tunneledflow to reduce classification complexity

第2题：

A GRE tunnel is configured between a local and a remote site. Where should the service policy be applied to classify packets based on the pretunnel header? （）

• A、in global configuration mode， apply the service policy and use the qos pre-classify
• B、in global configuration mode， apply the service policy but do not use the qos pre-classify command
• C、apply the service policy on the physical interface but do not use the qos pre-classify
• D、apply the service policy on the tunnel interface but do not use the qos pre-classify command 
• E、apply the service policy on the tunnel interface and use the qos pre-classify command

第3题：

Which two Cisco AutoQoS configuration statements are true？ （）

• A、the auto discovery qos command is supported on serial interfaces， subinterfaces， and virtual interfaces
• B、CEF must be enabled before configuring the auto discovery qos command
• C、the auto discovery qos privilege EXEC command must be configured on a router for several days to collect a sampling of data traffic
• D、the auto qos trust command relies on NBAR to provide VoIP classification
• E、the auto qos voip command configures the voip classification on routers and switches

第4题：

Which two statements are true about the various methods of implementing QoS？（）

• A、Cisco AutoQoS can be used repeatedly to apply a single QoS policy to multiple interfaces.
• B、Cisco AutoQoS includes an optional web-based GUI for automating the configuration of QoS services.
• C、Cisco AutoQoS provides capabilities to automate VoIP deployments.
• D、The auto qos global configuration command is used to configure Cisco AutoQoS.
• E、The Modular QoS CLI （MQC） is the best way to fine tune QoS configurations.
• F、The SDM QoS wizard is the fastest way to implement QoS.

第5题：

The Cisco AutoQoS feature is being used throughout the Company VOIP network.  Which three  statements about this feature are true？（）

• A、The "mls qos" global configuration command must be entered before configuring AutoQoS.
• B、CEF must be enabled.
• C、The "no auto qos voip" command is used to disable Cisco AutoQos and revoke all  configurations generated by Cisco AutoQos.
• D、CDP must be enabled.
• E、SNMP must be enabled.

第6题：

Which three statements are true about the application of QoS models？ （）

• A、 The DiffServ model requires applications to signal the network with QoS requirements.
• B、 The DiffServ model can be used to deliver QoS based upon IP precedence， or source and destination addresses.
• C、 The DiffServ model requires RSVP.
• D、 The best effort model is suitable for applications such as file transfer and e-mail
• E、 The IntServ model requires applications to signal the network with QoS requirements.
• F、 The IntServ model attempts to deliver a level of service based on the QoS specified by each packet

第7题：

Which two statements or sets of statements are true about the application of the qos pre-classify command？（）

• A、 If the classification policy is based upon the ToS byte， the qos pre-classify command is required because the ToS byte only appears in the inner IP header.
• B、 The ToS byte is copied to the outer header by default. Therefore， the qos pre-classify command is not necessary.
• C、 With GRE encapsulation， the qos pre-classify command is applied on the tunnel interface. This practice allows for different OoS configurations on each tunnel.
• D、 With GRE encapsulation， the qos pre-classify command is applied on the physical interface. This practice allows for different OoS configurations on each interface.
• E、 With IPsec encapsulation， the qos pre-classify command is applied on the physical interface. This practice allows for different OoS configurations on each interface.

第8题：

Choose the true statement regarding QoS pre-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.

第9题：

Which QoS preclassification option will require the use of the qos pre-classify command for the VPN traffic？ （）

• A、VPN traffic needs to be classified based on the Layer2 header information
• B、VPN traffic needs to be classified based on the IP precedence or DSCP
• C、VPN traffic needs to be classified based on IP flow or Layer 3 information， such as source and destination IP address
• D、VPN traffic with Authentication Header （AH） needs to preserve the ToS byte

第10题：

Which of the following is TRUE about the ping  -f command?（）

• A、 It is useful for diagnosing data dependent problems by filling the packet with the byte pattern following the "f" in the command line. 
• B、 It is useful for flooding from slow character based terminals since it only displays a dot "." for each packet sent in fast mode. 
• C、 It is useful for flooding from slow character based terminals since it only displays a dot "."       for each packet sent and a backspace on returned in fast mode. 
• D、 The command can only be run by root.