多选题What are two characteristics of the DiffServ model？（）Aservice guaranteeBtraffic that is divided into classesCnot scalable to large implementationsDQoS mechanisms that are used without prior signalingEapplications that signal their particular QoS and ba

第1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2题：

What is a drawback to using the IntServ model？（）

• A、RSVP that signals QoS requests per individual flow
• B、not scalable to large implementations
• C、admission control not supported
• D、use of dynamic port numbers 
• E、UDP not supported

第3题：

第4题：

What are two QoS mechanisms that are used to prevent packet loss？（）

• A、header compression
• B、payload compression
• C、low latency queuing （LLQ）
• D、weighted random early detection （WRED）
• E、traffic policing
• F、traffic shaping

第5题：

What are two characteristics of the DiffServ model？（）

• A、service guarantee
• B、traffic that is divided into classes
• C、not scalable to large implementations
• D、QoS mechanisms that are used without prior signaling
• E、applications that signal their particular QoS and bandwidth requirements

第6题：

Which two statements about the DiffServ  model are true？（）

• A、a class can be identified as a single application， multiple applications with similar service needs，or be based on the source or destination IP address
• B、a drawback of the DiffServ field in the MAC header to mark frames into behavior aggregates （BAs）
• C、DiffServ uses the DiffServ field in the MAC header to mark frames into behavior
• D、the DiffServ field occupies the same eight bits of the MAC header that were previously used for the ToS field
• E、the first six high-order bits of the DiffServ field are used to identify the Resource Reservation Protocol （RSVP） value
• F、the primary goal of DiffServ is scalability

第7题：

Which two statements are true about RSVP and the InServ QoS model？（）

• A、a drawback of implementing RSVP is the requirement to migrate to a supporting routing protocol
• B、RSVP uses DSCP to signal QoS requirements to routers 
• C、RSVP is a routing protocol
• D、RSVP is an IP protocol that uses IP protocol ID 46， and TCP/UDP ports 3455
• E、RSVP specifically provides a level of service for rate-sensitive and delay-sensitive traffic
• F、the flow-based approach of RSVP is ideal for large， scalable implementations such as the public internet

第8题：

What are two characteristics of the relationship between the Cisco PIN architecture and CiscoValidated Designs? （）(Choose two.)

• A、Cisco is focusing on Cisco Validated Designs as a means to driving integrated networks.
• B、Cisco is focusing on the PIN architecture as a means to driving integrated networks.
• C、The Cisco PIN architecture is a critical mechanism for supporting integrated markets because it can be implemented quickly.
• D、The Cisco Validated Designs program provides critical mechanisms for supporting integrated markets because the mechanisms can be implemented quickly.
• E、Cisco Validated Designs can be implemented quickly without customer input.

第9题：

Which two statements about the DiffServ model are true？ （）

• A、 A class can be identified as a single application， multiple applications with similar service needs， or be based on the source or destination IP addresses.
• B、 A drawback of the DiffServ model is that it does not provide backward compatibility with devices that can only use the ToS field.
• C、 DiffServ uses the DiffServ field in the MAC header to mark frames into behavior aggregates （BAs）. 
• D、 The DiffServ field occupies the same eight bits of the MAC header that were previously used for the ToS field.
• E、 The first six high-order bits of the DiffServ field are used to identify the Resource Reservation Protocol （RSVP） value.
• F、 The primary goal of DiffServ is scalability.

第10题：

Which two statements about the DiffServ QoS model are true？（）

• A、DiffServ requires RSVP to set up a path through the network to accommodate the requested QoS.
• B、Network traffic is identified by class， and the level of service is chosen for each class.
• C、The DiffServ model relies on a fairly simple mechanism to provide QoS over a wide range of equipment.
• D、RSVP enables the DiffServ model to provide end-to-end QoS.
• E、The DiffServ model is more scalable than the IntServ model.
• F、The flow-based approach of the DiffServ model is ideal for large scalable implementations such as the public Internet.