多选题Which two QoS classification and marking statements are true？ （）AIn a Frame Relay network， delay sensitive traffic is tagged with the discard eligible （DE） bit.BIn an MPLS network， the three most significant bits of the DSCP or the IP precedence of the

第1题：

Which two QoS classification and marking statements are true？ （）

• A、 In a Frame Relay network， delay sensitive traffic is tagged with the discard eligible （DE） bit.
• B、 In an MPLS network， the three most significant bits of the DSCP or the IP precedence of the IP packet are copied into the MPLS EXP field.
• C、 In an MPLS network， the MPLS EXP bits are used to identify up to 16 CoS values.
• D、 The differentiated services code point （DSCP） field consists of the first three bits of the IP precedence field in the header of an IP packet.
• E、 The 802.1Q standard uses a three bit field referred to as the user priority bits （PRI） to mark packets as belonging to a specific CoS.

第2题：

Which two statements are true about Unicast Reverse Path Forwarding Loose Mode？（）

• A、It is used in multihome network scenarios.
• B、It can be used with BGP to mitigate DoS and DDoS.
• C、It does not need to have CEF enabled.
• D、It is enabled via the interface level command ip verify unicast reverse-path.
• E、It cannot be used with "classification" access lists.

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 three statements are true about policing？ （）

• A、Out-of-profile packets are queued.
• B、It causes TCP retransmits.
• C、Marking and remarking are not supported.
• D、It does not respond to BECN and foresight messages.
• E、It uses a single- and two-bucket mechanism for metering.

第5题：

Which two statements about the best effort model for QoS are true？（）

• A、delay sensitive packets are given preferential treatment
• B、the default policy identifies a delay sensitive class and default class
• C、the default policy identifies a delay sensitive class， best effort class， and default class
• D、the model is highly scalable
• E、the model is still predominant on the internet F the model provides guaranteed service

第6题：

Which two QoS classification and marking statements are true？（）

• A、 In a Frame Relay network， delay sensitive traffic is tagged with the discard eligible （DE） bit.
• B、 In an MPLS network， the three most significant bits of the DSCP or the IP precedence of the IP packet are copied into the MPLS EXP field
• C、 In an MPLS network， the MPLS EXP bits are used to identify up to 16 CoS values.
• D、 The differentiated services code point （DSCP） field consists of the first three bits of the IP precedence field in the header of an IP packet.
• E、 The 802.10 standard uses a three bitfield referred to as the user priority bits （PRI） to mark packets as belonging to a specific CoS.

第7题：

Which two statements are true about L2TP tunnels?（） (Choose two.)

• A、Traffic is clear text
• B、Traffic is encrypted 
• C、They are initiated by the LNS
• D、They are initiated by the LAC

第8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9题：

Which two statements are true about traffic shaping？（）

• A、Out-of-profile packets are queued.
• B、It causes TCP retransmits.
• C、Marking/remarking is not supported.
• D、It does not respond to BECN and ForeSight Messages.
• E、It uses a single/two-bucket mechanism for metering.

第10题：

Which two statements about the QoS policy generation phase of the Cisco SDM QoS wizard are true？（）

• A、the SDM QoS wizard will create two real-time traffic classes to handle VoIP， voice signaling， and video packets
• B、the SDM QoS wizard will create three real-time traffic classes to handle VoIP， voice signaling， video， and video packets
• C、the SDM QoS wizard will create four real-time traffic classes to handle VoIP， voice signaling， video， and video streaming packets
• D、the SDM QoS wizard will create two business-critical traffic classes to handle transactional and  network management packets
• E、the SDM QoS wizard will create three business-critical traffic classes to handle transactional， network management， and routing packets
• F、the SDM QoS wizard will create four business-critical traffic classes to handle transactional， network management， routing， and best-effort packets