Juniper Juniper Certifications JN0-643 Questions & Answers

• Question 181:

  You are asked to configure an interface policer. You must ensure when the bandwidth limit and burst size are exceeded, that the packet receives a CoS parameter which increases the probability that the packet will be dropped if the queues are congested.

  Which policer action will accomplish this requirement?

  A. dscp 0

  B. loss-priority high

  C. ip-precedence 0

  D. loss-priority low

  Correct Answer: B

• Question 182:

  You are asked to reconfigure a CoS scheduler to limit the assured forwarding queue to a maximum of 75 percent of the available bandwidth. The assured forwarding queue uses a strict high priority queue. Which configuration parameter accomplishes this task?

  A. transmit-rate percent 75

  B. buffer-size percent 75

  C. shaping-rate percent 75

  D. shared-buffer percent 75

  Correct Answer: C

• Question 183:

  You must configure a multifield classifier on ge-1/0/0. This classifier must match only TCP traffic from port number 79, set the loss priority to high, and classify the traffic as expedited- forwarding. The inbound traffic has no previous CoS markings.

  Which configuration meets these requirements?

  A. [edit firewall] user@switch# show filter ef_classifier_mf term 1 { from { protocol tcp; destination-port 79; } then { loss-priority high; forwarding-class expedited-forwarding; } [...] }

  B. [edit firewall] user@switch# show filter ef_classifier_mf term 1 { from { protocol tcp; source-port 79; } then { loss-priority high; forwarding-class expedited-forwarding; }

  [...]

  }

  C. [edit firewall] user@switch# show filter ef_classifier_mf term 1 { from { protocol tcp; destination-port 79; } then { loss-priority low; forwarding-class expedited-forwarding; } [...] }

  D. [edit firewall] user@switch# show filter ef_classifier_mf term 1 { from { protocol tcp; source-port 79; dscp ef; } then { loss-priority high; accept; } [...] }

  Correct Answer: B

• Question 184:

  You are asked to configure a CoS weighted tail drop profile on your EX Series switch that causes all traffic in the best effort queue to drop when the queue is 90 percent full.

  Which configuration will accomplish this request?

  A. [edit class-of-service] drop-profiles { be_dropp { fill-level 90; drop-probability 100; } }

  B. [edit class-of-service] drop-profiles { be_dropp { interpolate { fill-level 90; drop-probability 100; } } }

  C. [edit class-of-service] drop-profiles { be_dropp { fill-level 90; } }

  D. [edit class-of-service] drop-profiles { be_dropp { fill-level 90; drop-probability 90; } }

  Correct Answer: C

• Question 185:

  You are asked to implement CoS on an EX Series switch. You attempt to configure the priority for the voice and data queue schedulers to medium-high and medium-low priority, respectively. However, you notice that the only parameters available for the priority is strict high and low.

  Why are strict high and low the only available parameters for configuration?

  A. The loss priority for the queues must first be set to medium-low and medium-high, respectively.

  B. The switch only supports the strict high and low queue priorities.

  C. The shared buffer feature must be configured prior to configuring scheduler priority.

  D. The scheduler must be applied to an interface prior to configuring scheduler priority.

  Correct Answer: B

• Question 186:

  -- Exhibit -[edit class-of-service]

  drop-profiles {

  test-drop {

  fill-level 20 drop-probability 35;

  fill-level 55 drop-probability 60;

  fill-level 70 drop-probability 80;

  fill-level 95 drop-probability 100;

  }

  }

  -- Exhibit -

  Click the Exhibit button.

  According to the configuration shown in the exhibit, what percentage of the traffic will be dropped when the queue fill level reaches 65 percent?

  A. 25

  B. 50

  C. 58

  D. 60

  Correct Answer: D

• Question 187:

  You notice that an interface receiving traffic from multiple devices with no user-configured CoS parameters has been assigned the ieee802.1p-default classifier.

  What is the port type assigned to this interface?

  A. access port

  B. tagged access port

  C. trunk port

  D. designated port

  Correct Answer: C

• Question 188:

  You just configured an interface as an access port and it is up and passing traffic. However, you notice that all traffic transiting this interface is being classified as best effort.

  Which default BA classifier is causing this behavior?

  A. ieee8021p-default

  B. ieee8021p-untrust

  C. dscp-default

  D. dscp-ipv6-default

  Correct Answer: B

• Question 189:

  On SRX Series devices, in which order does CoS process ingress packets?

  A. multifield classifier, policer, forwarding policy, behavior aggregate classifier

  B. multifield classifier, forwarding policy, policer, behavior aggregate classifier

  C. behavior aggregate classifier, policer, multifield classifier, forwarding policy

  D. behavior aggregate classifier, multifield classifier, policer, forwarding policy

  Correct Answer: D

• Question 190:

  A network administrator is configuring CoS on a switch and assigns forwarding classes shown below:

  class-of-service {

  forwarding-classes {

  class best-effort queue-num 0;

  class bulk-data queue-num 1;

  class critical queue-num 3;

  class voice queue-num 6;

  class call-signal queue-num 3;

  }

  }

  Based on the configuration, which action prioritizes call-signal traffic over critical traffic?

  A. Assign call-signal traffic and critical traffic to different schedulers.

  B. Assign call-signal traffic and critical traffic to different scheduler maps.

  C. Assign a loss priority of high to the packets in the critical forwarding class and set priority high in the scheduler configuration.

  D. Assign a loss priority of high to the packets in the critical forwarding class and configure drop profiles in the scheduler configuration.

  Correct Answer: D