Free 400-007 Exam Braindumps (page: 12)

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You want to mitigate failures that are caused by STP loops that occur before UDLD detects the failure or that are caused by a device that is no longer sendingBPDUs. Which mechanism do you use along with UDLD?

  1. BPDU guard
  2. root guard
  3. loop guard
  4. BPDU filtering

Answer(s): C

Explanation:

Loop guard is a Spanning Tree Protocol (STP) feature that helps prevent forwarding loops and blackholing of traffic by identifying and acting on logical one-way links that would otherwise go undetected.

UDLD (Unidirectional Link Detection) is a Layer 2 protocol that helps to prevent forwarding loops and blackholing of traffic by detecting unidirectional links. However, UDLD can take some time to detect a unidirectional link, and it may not detect a link that is no longer sending BPDUs.

Loop guard can be used along with UDLD to help mitigate failures that are caused by STP loops that occur before UDLD detects the failure or that are caused by a device that is no longer sending BPDUs. Loop guard will put a port into err-disable state if it detects a unidirectional link or if it does not receive BPDUs for a specified period of time.

The other options are not as effective for mitigating failures that are caused by STP loops. Option A, BPDU guard, will put a port into err-disable state if it receives BPDUs from a device that is not the designated bridge for the port. Option B, root guard, will put a port into err-disable state if it receives BPDUs that indicate that the port is the root bridge. Option D, BPDU filtering, will prevent BPDUs from being received on a port.



Company XYZ needs advice in redesigning their legacy Layer 2 infrastructure. Which technology should be included in the design to minimize or avoid convergence delays due to STP or FHRP and provide a loop-free topology?

  1. Use BFD.
  2. Use switch clustering in the core/distribution layer.
  3. Use spanning-tree PortFast.
  4. Use switch clustering in the access layer.

Answer(s): B

Explanation:

Switch clustering is a technology that allows multiple switches to be grouped together so that they appear as a single logical switch. This can help to improve convergence times by reducing the number of switches that need to be updated when a change occurs.

Spanning-tree PortFast is a feature that allows ports to be put into the forwarding state immediately, bypassing the STP listening and learning states. This can help to improve convergence times, but it can also introduce loops into the network if not used carefully.

BFD is a protocol that provides fast failure detection for Layer 2 and Layer 3 links. This can help to improve convergence times by reducing the time it takes for switches to detect link failures.

FHRP (First Hop Redundancy Protocol) is a protocol that provides redundancy for Layer 2 routing. This can help to improve availability, but it does not directly affect convergence times.

Therefore, the best technology to include in the design to minimize or avoid convergence delays due to STP or FHRP and provide a loop-free topology is switch clustering.

Here are some additional reasons why switch clustering is a good choice for this scenario:

-It can be implemented in the core/distribution layer, which is where STP loops are most likely to occur.
-It is a relatively simple technology to implement and manage.
-It can be used to improve convergence times for both STP and FHRP.
Here are some additional reasons why the other options are not as good a choice:

-Spanning-tree PortFast can introduce loops into the network if not used carefully.
-BFD is a good technology for fast failure detection, but it does not directly affect convergence times.
-FHRP can improve availability, but it does not directly affect convergence times.
-



DRAG DROP (Drag and Drop is not supported)
Drag and drop the multicast protocols from the left onto the correct design situations on the right. Not all options are used.
Select and Place:

  1. See Explanation section for answer.

Answer(s): A

Explanation:



Which function is performed at the access layer of the three-layer hierarchical network design model?

  1. fast transport
  2. reliability
  3. fault isolation
  4. redundancy and load balancing
  5. QoS classification and marking boundary

Answer(s): E

Explanation:

The access layer of the three-layer hierarchical network design model is responsible for connecting end-user devices to the network. This layer is also responsible for providing QoS (Quality of Service) classification and marking.

QoS classification is the process of identifying different types of traffic and marking them with different values. This allows routers and switches to prioritize different types of traffic, which can improve performance for time-sensitive applications.

QoS marking is the process of adding a QoS tag to a packet. This tag identifies the type of traffic and allows routers and switches to prioritize different types of traffic.

Therefore, the function of QoS classification and marking is performed at the access layer of the three-layer hierarchical network design model.



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Post your Comments and Discuss Cisco® 400-007 exam with other Community members:

RLCCIRCUIT commented on July 15, 2024
I passed the exam with 848 on 12th July. This dump covers most of the questions, I only met 4 new ones. Thanks very much. I will get other exam dumps here.
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