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Jul

Do You Need the New QoS Class? Answers and Explanations

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Posted by Anthony Sequeira, #15626 in CCIE R&S, QoS

Try these questions on for size! Learn all this and much more in the new QoS class – woohoo!

1. Based on the following configuration, what traffic will be policed?

class-map C_MUSIC

match protocol kazaa2

match protocol napster

class-map match-any C_WEB

match protocol http

match class-map C_MUSIC

policy-map P_WEB

class C_WEB

police 64000

interface serial 0/0

service-policy output P_WEB

A. All Kazaa version 2 traffic is policed

B. All Napster traffic is policed

C. All web traffic is policed

D. All Kazaa version 2, Napster, and web traffic is policed

E. No traffic is policed

2. You are configuring a Cisco Catalyst 3550 switch port to trust CoS markings if, and only if, the marking originated from a Cisco IP Phone. In an attempt to perform this configuration, you enter the mls qos trust device cisco-phone command. However, your configuration does not seem to be working properly. Why is the switch not trusting CoS markings coming from an attached Cisco IP Phone?

A. A Cisco Catalyst 3550 switch supports the mls qos trust device cisco-phone command, but the Cisco Catalyst 2950 does not support this command.

B. The mls qos trust cos command is missing.

C. The mls qos trust extend command is missing.

D. The mls qos cos 5 command is missing.

3. You administer a network that transports both voice and interactive video traffic. Since these traffic types are both latency-sensitive, you decide to implement the following configuration. Which statement is true regarding the configuration?

class-map C_VOICE

match protocol rtp audio

class-map C_VIDEO

match protocol rtp video

policy-map P_HIGH_PRIORITY

class C_VOICE

priority percent 15

class C_VIDEO

priority percent 35

class class-default

fair-queue

interface serial 0/0

service-policy output P_HIGH_PRIORITY

A. The configuration results in three queues, one for the C_VOICE class, one for the C_VIDEO class, and one queue for the class-default class.

B. The configuration results in two queues, one priority queue and one queue for the class-default class.

C. The class-default class uses FIFO as its queuing mechanism for traffic flows within its queue.

D. The two priority queues use WFQ for queuing traffic within those queues.

4. CB-WRED is configured using the random-detect command. Which two of the following statements are true concerning the random-detect command? (Choose 2)

A. The random-detect command cannot be issued for the class-default class.

B. The random-detect command cannot be issued for the priority class(es).

C. The random-detect command must be issued in conjunction with the bandwidth command (with the exception of the class-default class).

D. The random-detect command should be issued in conjunction with the priority command.

5. Consider the following configuration:

class-map TRANSACTIONAL

match protocol http

policy-map CBPOLICING

class TRANSACTIONAL

police 128000 conform-action set-dscp-transmit af11 exceed-action set-dscp-transmit af13 violate-action drop

interface serial 0/1

service-policy input CBPOLICING

What type of class-based policing configuration is represented by this configuration?

A. Single rate, single bucket

B. Single rate, dual bucket

C. Dual rate, single bucket

D. Dual rate, dual bucket

6. You configure CB-Shaping by issuing the command shape peak 8000 2000 2000. This configuration shapes to what peak rate?

A. 4000 bps

B. 8000 bps

C. 16000 bps

D. 32000 bps

7. You are configuring Multilink PPP (MLP) as your Link Fragmentation and Interleaving (LFI) mechanism for a WAN link. Identify the correct statements regarding the configuration of MLP. (Choose 2)

A. The configuration of Multilink PPP requires at least two physical links (e.g. two serial interfaces).

B. The IP address is removed from any serial interface that makes up the MLP bundle.

C. Any policy-map that was previously assigned to a physical interface should be reassigned to the multilink interface, that the physical interface is associated with, in order for the policy to take effect.

D. The virtual multilink interface does not use an IP address. Rather, it uses the IP unnumbered feature which allows the multilink interface to share an IP address with the multilink bundle member that has the highest IP address.

1. Based on the following configuration, what traffic will be policed?

class-map C_MUSIC
  match protocol kazaa2
  match protocol napster
!
class-map match-any C_WEB
  match protocol http
  match class-map C_MUSIC
!
policy-map P_WEB
  class C_WEB
    police 64000
!
interface serial 0/0
  service-policy output P_WEB

A. All Kazaa version 2 traffic is policed

B. All Napster traffic is policed

C. All web traffic is policed

D. All Kazaa version 2, Napster, and web traffic is policed

E. No traffic is policed

Answer:

Explanation:

The C_MUSIC class-map does not specify the match-any or match-all option. The default is match-all. Therefore, for traffic to be classified in the C_MUSIC class-map, a packet would simultaneously have to be a Kazaa version 2 packet and a Napster packet, which isn’t possible.

The C_WEB class-map uses the match-any option, meaning that traffic will be classified in this class-map if it is HTTP traffic or if it is traffic that was classified in the C_MUSIC class-map. Since, no traffic will be classified in the C_MUSIC class-map, as described above, the only traffic that will be classified by the C_WEB class-map is HTTP traffic.

The policy-map P_WEB is configured to police (i.e. rate limit) traffic classified by the C_WEB class-map to a bandwidth of 64 kbps. (NOTE: The default conform-action is transmit, and the default exceed-action is drop.) Since only HTTP (i.e. web) traffic is matched by the C_WEB class-map, web traffic is the only traffic that is policed. Continue Reading

Tags: ccie, exam, lab, practice, QoS

Jun

Do You Need the New INE QoS Class?

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