CCNP Voice FAQ: Implementing AutoQoS

CCNP Voice FAQ: Implementing AutoQoS

Q1. Which of the following is not a key benefit of Cisco AutoQoS?
A. It automates and simplifies QoS deployment and provisioning.
B. AutoQoS results are maintenance free and can’t be tuned.
C. It reduces configuration errors.
D. It allows customers to retain complete control over their QoS configuration.

Answer: B

Q2. Which of the following statements is true about the evolution of Cisco AutoQoS?
A. Cisco AutoQoS has evolved from AutoQoS VoIP to AutoQoS for Enterprise. AutoQoS for Enterprise extends the AutoQoS capabilities beyond VoIP, but it is only supported on Catalyst Switches.

B. Cisco AutoQoS has evolved from AutoQoS VoIP to AutoQoS for Enterprise. AutoQoS for Enterprise extends the AutoQoS capabilities beyond VoIP, and it has an autodiscovery step.

C. Cisco AutoQoS has evolved from basic AutoQoS to AutoQoS VoIP. AutoQoS VoIP extends the AutoQoS capabilities to support Voice over IP.

D. Cisco AutoQoS has evolved from basic AutoQoS to AutoQoS VoIP. AutoQoS VoIP extends the AutoQoS capabilities to support Voice over IP, but it is supported only on Cisco routers.

Answer: B

Q3. Which of the following is not one of the five key elements of QoS deployment?
A. Intrusion detection
B. Application classification and policy generation
C. Configuration and monitoring (reporting)
D. Consistency

Answer: A

Q4. Which of the following is not true about NBAR protocol discovery?
A. NBAR protocol discovery is able to identify and classify static port applications.

B. NBAR protocol discovery is able to identify and classify dynamic port applications.

C. NBAR protocol discovery is able to identify and classify HTTP applications based on URL, MIME type, or host name.

D. NBAR protocol discovery is able to identify and classify IP applications only

Answer: D

Q5. Which of the following is a Cisco AutoQoS router configuration prerequisite?
A. No QoS policy (service) policy can be applied to the interface.
B. CEF must be enabled on the interface.
C. Correct bandwidth must be configured on the interface.
D. All of the above.

Answer: D

Q6. In deploying Cisco AutoQoS for Enterprise on routers, what is Step 1 (or Phase 1) of the twostep (2-phase) approach?
A. Profiling the data using autodiscovery
B. Assigning the appropriate bandwidth and scheduling parameters
C. Mapping applications to their corresponding DiffServ classes
D. Enabling CEF

Answer: A

Q7. Which of the following is not a Cisco LAN switch AutoQoS verification command?
A. show auto qos
B. show auto qos interface interface
C. show auto discovery qos
D. show mls qos maps [cos-dscp | dscp-cos]

Answer: C

Q8. Which of the following is not one of the three most common Cisco AutoQoS issues that can arise?
A. Too many traffic classes are generated; classification is overengineered.

B. The configuration that AutoQoS generates does not adapt to changing network traffic conditions automatically.

C. The configuration that AutoQoS generates is not modifiable.

D. The configuration that AutoQoS generates fits common network scenarios but does not fit some circumstances, even after extensive autodiscovery.

Answer: C

Q9. Which of the following is a possible way to tune and modify the class maps or policy maps that AutoQoS generates?
A. Do it directly at the router command-line interface (CLI) using MQC

B. Use Cisco QoS Policy Manager (QPM)

C. Copy the class maps or policy maps into a text editor, and modify the configuration offline

D. All of the above

Answer: D

Q10. Besides NBAR and ACLs, which of the MQC classification options can you use to tune an AutoQoS-generated configuration?
A. match input interface, match ip dscp, match ip precedence, match ip cos
B. match input interface, match ip dscp, match ip precedence, match ip rtp
C. match ip dscp, match ip precedence, match ip rtp, match ip cos
D. match input interface, match ip dscp, match ip cos, match ip rtp

Answer: B

Q11. List at least three key benefits of Cisco AutoQoS.

Answer: Cisco AutoQoS has many benefits, including the following:

  • It uses Cisco IOS built-in intelligence to automate generation of QoS configurations for most common business scenarios.
  • It protects business-critical data applications in the Enterprise to maximize their availability.
  • It simplifies QoS deployment.
  • It reduces configuration errors.
  • It makes QoS deployment cheaper, faster, and simpler.
  • It follows the DiffServ model.
  • It allows customers to have complete control over their QoS configuration.
  • It enables customers to modify and tune the configurations that Cisco AutoQoS automatically
  • generates to meet their specific needs or changes to the network conditions.

Q12. What are the two phases of AutoQoS evolution?

Answer: The two phases of AutoQoS evolution are AutoQoS VoIP and AutoQoS for Enterprise.

Q13. What are the five key elements of QoS deployment that Cisco AutoQoS addresses?

Answer: Cisco AutoQoS addresses the following five key elements:

  • Application classification
  • Policy generation
  • Configuration
  • Monitoring and reporting
  • Consistency

Q14. Which application types is NBAR protocol discovery able to identify and classify?

Answer: NBAR protocol discovery is able to identify and classify the following:

  • Applications that target a session to a well-known (UDP/TCP) destination port number, referred to as static port applications
  • Applications that start a control session using a well-known port number but negotiate another port number for the session, referred to as dynamic port applications
  • Some non-IP applications
  • HTTP applications based on URL, MIME type, or host name

Q15. On what types of router interfaces or PVCs can you enable Cisco AutoQoS?

Answer: You can enable Cisco AutoQoS on the following types of router interfaces or PVCs:

  • Serial interfaces with PPP or HDLC encapsulation.
  • Frame Relay point-to-point subinterfaces. (Multipoint is not supported.)
  • ATM point-to-point subinterfaces (PVCs) on both slow (<=768 kbps) and fast serial (>768 kbps) interfaces.
  • Frame Relay-to-ATM interworking links

Q16. What are the router prerequisites for configuring AutoQoS?

Answer: The router prerequisites for configuring AutoQoS are as follows:

  • The router cannot have a QoS policy attached to the interface.
  • You must enable CEF on the router interface (or PVC).
  • You must specify the correct bandwidth on the interface or subinterface.
  • You must configure a low-speed interface (<= 768 Kbps) and an IP address.

Q17. What are the two steps (or phases) of AutoQoS for Enterprise?

Answer: Following are the two steps (or phases) of AutoQoS for Enterprise:

  1. Traffic is profiled using autodiscovery. You do this by entering the auto qos discovery command in the interface configuration mode.
  2. MQC-based QoS policies are generated and deployed. You do this by entering the auto qos command in interface configuration mode.

Q18. List at least two commands for verifying AutoQoS on Cisco routers.

Answer: Following are the commands for verifying AutoQoS on Cisco routers:

  • show auto discovery qos allows you to examine autodiscovery results.
  • show auto qos allows you to examine Cisco AutoQoS templates and initial configuration.
  • show policy-map interface allows you to explore interface statistics for autogenerated policy.

Q19. List at least two commands for verifying AutoQoS on Cisco LAN switches.

Answer: The commands for verifying AutoQoS on Cisco LAN switches are as follows:

  • show auto qos allows you to examine Cisco AutoQoS templates and the initial configuration.
  • show policy-map interface allows you to explore interface statistics for autogenerated policy.
  • show mls qos maps allows you to examine CoS-to-DSCP maps.

Q20. What are the three most common Cisco AutoQoS issues that can arise, and their corresponding solutions?

Answer: The three most common Cisco AutoQoS issues that can arise, and their corresponding solutions, are as follows:

  • Too many traffic classes are generated; classification is overengineered.
    Solution: Manually consolidate similar classes to produce the number of classes needed.
  • The configuration that AutoQoS generates does not automatically adapt to changing network traffic conditions.
    Solution: Run Cisco AutoQoS discovery on a periodic basis, followed by re-enabling of Cisco AutoQoS.
  • The configuration that AutoQoS generates fits common network scenarios but does not fit some circumstances, even after extensive autodiscovery.
    Solution: Manually fine-tune the AutoQoS-generated configuration.

Q21. List at least three pieces of information that can be obtained from the output of the show auto qos command.

Answer: You can obtain the following information from the output of the show auto qos command:

  • Number of traffic classes identified (class maps)
  • Traffic classification options selected (within class maps)
  • Traffic marking options selected (within policy maps)
  • Queuing mechanisms deployed, and their corresponding parameters (within policy maps)
  • Other QoS mechanisms deployed (within policy maps)
  • Where the autogenerated policies are applied: on the interface, subinterface, or PVC

Q22. What are the two major reasons for modifying the configuration that AutoQoS generates?

Answer: Following are the two major reasons for modifying the configuration that AutoQoS generates:

  • The AutoQoS-generated commands do not completely satisfy the specific requirements of the Enterprise network.
  • The network condition, policies, traffic volume and patterns, and so on might change over time, rendering the AutoQoS-generated configuration dissatisfying.

Q23. Specify two methods for modifying and tuning the AutoQoS-generated class maps and policy maps.

Answer: You can modify and tune the AutoQoS-generated class maps and policy maps by doing the following:

  • Using Cisco QoS Policy Manager (QPM).
  • Directly entering the commands one at a time at the router command-line interface using MQC.
  • Copying the existing configuration, a class map for example, into a text editor and modifying the configuration using the text editor, offline. Next, using CLI, remove the old undesirable configuration and then add the new configuration by copying and pasting the text from the text editor. This is probably the easiest way.

Q24. In addition to using NBAR and ACLs, what classification options does MQC offer?

Answer:
14-1
14-2

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