多选题Which three traffic descriptors are typically used as QoS markings for packets or frames entering the network？（）Aprotocol typeBCoSCDSCPDIP precedenceEdestination addressFinput interface

第1题：

Which three QoS mechanisms can be configured to improve VoIP quality on a converged  network？（）

• A、The use of a queuing method that will give VoIP traffic strict priority over other traffic  
• B、The use of RTP header compression for the VoIP traffic.
• C、The proper classification and marking of the traffic as close to the source as possible
• D、The use of 802.1QinQ trunking for VoIP traffic
• E、The use of WRED for the VoIP traffic

第2题：

You work as a network technician. Your boss is interested in the QoS technology in the context ofvideo traffic. What can be said of application of this technology in this type of network？（）

• A、The access layer is the initial point at which traffic enters the network. Traffic is marked （orremarked） at Layers 2 and 3 by the access switch as it enters the network， or is "trusted" that it isentering the network with the appropriate tag
• B、No traffic marking occurs at the core layer. Layer 2/3 QoS tags are trusted from distributionlayer switches and used to prioritize and queue the traffic as it traverses the core
• C、Traffic inbound from the access layer to the distribution layer can be trusted or reset dependingupon the ability of the access layer switches. Priority access into the core is provided based onLayer 3 QoS tags
• D、IP precedence， DSCP， QoS group， IP address， and ingress interface are Layer 2 characteristics that are set by the access layer as it passes traffic to the distribution layer. Thedistribution layer， once it has made a switching decision to the core layer， strips these off
• E、MAC address， Multiprotocol Label Switching （MPLS）； the ATM cell loss priority （CLP） bit， theFrame Relay discard eligible （DE） bit， and ingress interface are established by the voicesubmodule （distribution layer） as traffic passes to the core layer
• F、The distribution layer inspects a frame to see if it has exceeded a predefined rate of trafficwithin a certain time frame， which is typically a fixed number internal to the switch. If a frame isdetermined to be in excess of the predefined rate limit， the CoS value can be marked up in a waythat results in the packet being dropped

第3题：

When Cisco SDM is used to generate QoS policy， various QoS classes will be created and assigned a percentage of the interface bandwidth. Which three statements indicate the default bandwidth values that are assigned by SDM for outgoing traffic on a WAN interface？ （）

• A、 Voice traffic will be assigned 47% of the interface bandwidth.
• B、 Voice call signaling will be assigned 33% of the interface bandwidth.
• C、 Telnet， SSH， and other traffic that is generated to manage the router is assigned 5% of the interface bandwidth.
• D、 Best-effort traffic will be assigned 38% of the interface bandwidth.
• E、 Routing protocol traffic will be assigned 5% of the interface bandwidth.
• F、 Transactional traffic will be assigned 5% of the interface bandwidth.

第4题：

Which IOS QoS mechanism is used strictly to rate limit traffic destinedto the router itself？（）

• A、 Class-Based Policing
• B、 Control Plane Policing
• C、 Dual-Rate Policier
• D、 Single-Rate Policier
• E、 Class-BasedTraffic Shaper

第5题：

Which three characteristics of the traffic flow are taken into consideration when the QoS-for-VPNs feature （QoS pre-classify） provides packet classification and applies appropriate QoS service on tunnel interfaces？（）

• A、IP precedence bits
• B、DSCP bits
• C、original port numbers
• D、DE bits
• E、source IP address
• F、destination IP address

第6题：

What are three traffic descriptors that are used by the classification process to categorize packets that require special OoS handling？（）

• A、Resource Reservation Protocol （RSVP）
• B、IP precedence
• C、traffic shaping
• D、trust boundaries
• E、DSCP
• F、application

第7题：

Which statement is true about the SDM QoS wizard and its ability to enable a QoS policy on router interfaces？（）

• A、QoS can be enabled on interfaces used for Easy VPN clients
• B、QoS can be enabled on IPsec VPN interfaces and tunnels
• C、QoS can be enabled on interfaces with an existing QoS policy
• D、the QoS policy can be enabled for incoming and outgoing traffic on the interface

第8题：

Which two QoS statements are true about the use of the SDM QoS wizard？（）

• A、Business-critical traffic includes VoIP and voice signaling packets.
• B、SDM can be used to configure a basic QoS policy for incoming traffic on WAN interfaces and IPsec tunnels.
• C、SDM can provide QoS for real-time traffic and business-critical traffic.
• D、SDM creates a custom-queuing （CQ） or a priority-queuing （PQ） policy.
• E、SDM creates a low latency queuing （LLQ） service policy with its associated classes.
• F、When allocating bandwidth， values can be entered in either bandwidth percentage or kilobytes per second （kBps）.

第9题：

Which three practices are important to the implementation of a DiffServ QoS architecture？（）

• A、 Because services are allocated throughout the network before the transmission of data begins， traffic classes can be guaranteed QoS services.
• B、 Traffic classes are marked with Layer 2 markings to allow for more granularity in identifying traffic classes.
• C、 Traffic classes are marked with Layer 3 markings to allow them to traverse different network types without loss of QoS information.
• D、 Traffic classes allow networks to provide proper QoS treatment of packets without applications having to request services.
• E、 Based upon the network capabilities， QoS markings are placed on packets as needed throughout the network to allow for proper QoS treatment of packets.
• F、 QoS markings are placed on packets as close to the network edge as possible to allow distribution and core devices to determine QoS actions as quickly as possible.

第10题：

Which three traffic descriptors are typically used as QoS markings for packets or frames entering the network？（）

• A、protocol type
• B、CoS
• C、DSCP
• D、IP precedence
• E、destination address
• F、input interface