• Recent Posts

  • AmazonExam

  • Braindumps

    Easy Pass Exams!
  • Testking

    Easy Pass Exams!
  • ExamCollection

    Easy Pass Exams!
  •  

    HOT 70-410 Exam VCE Dumps >> Free Download

    HOT 70-411 Exam VCE Dumps >> Free Download

    HOT 70-412 Exam VCE Dumps >> Free Download

    HOT 70-413 Exam VCE Dumps >> Free Download

    HOT 70-414 Exam VCE Dumps >> Free Download

    HOT 70-415 Exam VCE Dumps >> Free Download

    HOT 70-416 Exam VCE Dumps >> Free Download

    HOT 70-417 Exam VCE Dumps >> Free Download

    NEW 70-432 Exam VCE Dumps >> Free Download

    NEW 70-448 Exam VCE Dumps >> Free Download

    NEW 70-457 Exam VCE Dumps >> Free Download

    NEW 70-458 Exam VCE Dumps >> Free Download

    NEW 70-459 Exam VCE Dumps >> Free Download

    HOT 70-460 Exam VCE Dumps >> Free Download

    HOT 70-461 Exam VCE Dumps >> Free Download

    HOT 70-462 Exam VCE Dumps >> Free Download

    HOT 70-463 Exam VCE Dumps >> Free Download

    HOT 70-464 Exam VCE Dumps >> Free Download

    HOT 70-465 Exam VCE Dumps >> Free Download

    HOT 70-466 Exam VCE Dumps >> Free Download

    HOT 70-467 Exam VCE Dumps >> Free Download

    HOT 70-469 Exam VCE Dumps >> Free Download

    NEW 70-470 Exam VCE Dumps >> Free Download

    NEW 70-480 Exam VCE Dumps >> Free Download

    NEW 70-481 Exam VCE Dumps >> Free Download

    NEW 70-482 Exam VCE Dumps >> Free Download

    HOT 70-483 Exam VCE Dumps >> Free Download

    NEW 70-484 Exam VCE Dumps >> Free Download

    NEW 70-485 Exam VCE Dumps >> Free Download

    NEW 70-486 Exam VCE Dumps >> Free Download

    NEW 70-487 Exam VCE Dumps >> Free Download

    HOT 70-488 Exam VCE Dumps >> Free Download

    NEW 70-489 Exam VCE Dumps >> Free Download

    NEW 70-490 Exam VCE Dumps >> Free Download

    NEW 70-491 Exam VCE Dumps >> Free Download

    NEW 70-492 Exam VCE Dumps >> Free Download

    NEW 70-494 Exam VCE Dumps >> Free Download

    NEW 70-496 Exam VCE Dumps >> Free Download

    NEW 70-497 Exam VCE Dumps >> Free Download

    NEW 70-498 Exam VCE Dumps >> Free Download

    NEW 70-499 Exam VCE Dumps >> Free Download

    NEW 70-511 Exam VCE Dumps >> Free Download

    NEW 70-513 Exam VCE Dumps >> Free Download

    NEW 70-515 Exam VCE Dumps >> Free Download

    NEW 70-516 Exam VCE Dumps >> Free Download

    NEW 70-517 Exam VCE Dumps >> Free Download

    HOT 70-532 Exam VCE Dumps >> Free Download

    HOT 70-533 Exam VCE Dumps >> Free Download

    HOT 70-534 Exam VCE Dumps >> Free Download

    NEW 70-573 Exam VCE Dumps >> Free Download

    NEW 70-576 Exam VCE Dumps >> Free Download

    NEW 70-640 Exam VCE Dumps >> Free Download

    NEW 70-642 Exam VCE Dumps >> Free Download

    NEW 70-646 Exam VCE Dumps >> Free Download

    NEW 70-659 Exam VCE Dumps >> Free Download

    NEW 70-662 Exam VCE Dumps >> Free Download

    NEW 70-663 Exam VCE Dumps >> Free Download

    NEW 70-667 Exam VCE Dumps >> Free Download

    NEW 70-668 Exam VCE Dumps >> Free Download

    NEW 70-673 Exam VCE Dumps >> Free Download

    HOT 70-680 Exam VCE Dumps >> Free Download

    NEW 70-685 Exam VCE Dumps >> Free Download

    NEW 70-686 Exam VCE Dumps >> Free Download

    NEW 70-687 Exam VCE Dumps >> Free Download

    HOT 70-688 Exam VCE Dumps >> Free Download

    NEW 70-689 Exam VCE Dumps >> Free Download

    NEW 70-692 Exam VCE Dumps >> Free Download

    NEW 70-694 Exam VCE Dumps >> Free Download

    NEW 70-695 Exam VCE Dumps >> Free Download

    NEW 70-696 Exam VCE Dumps >> Free Download

    NEW 70-697 Exam VCE Dumps >> Free Download

    NEW 70-980 Exam VCE Dumps >> Free Download

    NEW 70-981 Exam VCE Dumps >> Free Download

    NEW 74-335 Exam VCE Dumps >> Free Download

    NEW 74-338 Exam VCE Dumps >> Free Download

    NEW 74-343 Exam VCE Dumps >> Free Download

    NEW 74-344 Exam VCE Dumps >> Free Download

    HOT 74-409 Exam VCE Dumps >> Free Download

    NEW 74-674 Exam VCE Dumps >> Free Download

    NEW 74-678 Exam VCE Dumps >> Free Download

    HOT 74-697 Exam VCE Dumps >> Free Download

    NEW 77-427 Exam VCE Dumps >> Free Download

  • « | Main | »

    CCIE R&S 350-001 Q&As – Implement Spanning Tree Protocol (STP)(16-20)

    By admin | June 18, 2014

    Tagged with:

    Section 1 – Implement Spanning Tree Protocol (STP)

    QUESTION 16
    The network administrator wants to enable an EtherChannel between two switches in "on" mode. The administrator connects the cables and enables the interfaces, but while configuring the EtherChannel in the first switch, a spanning-tree loop was detected. Which two of these procedures can avoid this problem? (Choose two.)
    A.    Configure the EtherChannel as "desirable" first.
    B.    Assign all interfaces to the same VLAN.
    C.    Disable PortFast on the interfaces in the EtherChannels.
    D.    Disable all interfaces first.
    E.    Fast Ethernet and Gigabit Ethernet ports cannot be assigned to the same EtherChannel.
    F.    Fix cabling problems.
    Answer: AD

    QUESTION 17
    While deploying a new switch, you accidently connect ports 3/12 and 3/18 together, creating a loop. STP detected it and placed port 3/18 in blocking mode. Why did STP not place port 3/12 in blocking mode instead?
    A.    Port 3/12 was already up and forwarding before the loop was created.
    B.    Port priority is based on lowest priority and lowest port number.
    C.    You connected the wire on port 3/18 last.
    D.    None of the above, it is purely random.
    Answer: B

    QUESTION 18
    Prior to 802.1w, Cisco implemented a number of proprietary enhancements to 802.1D to improve convergence in a Layer 2 network. Which statement is correct?
    A.    Only UplinkFast and BackboneFast are specified in 802.1w; PortFast must be manually configured.
    B.    Only PortFast is specified in 802.1w; UplinkFast and BackboneFast must be manually configured.
    C.    None of the proprietary Cisco enhancements are specified in 802.1w.
    D.    PortFast, UplinkFast, and BackboneFast are specified in 802.1w.
    Answer: D
    Explanation:
    Spanning-tree PortFast causes a spanning-tree port to enter the forwarding state immediately, bypassing the listening and learning states. You can use PortFast on switch ports connected to a single workstation or server to allow those devices to connect to the network immediately, rather than waiting for spanning tree to converge.
    UplinkFast provides fast convergence after a spanning-tree topology change and achieves load balancing between redundant links using uplink groups. An uplink group is a set of ports (per VLAN), only one of which is forwarding at any given time. Specifically, an uplink group consists of the root port (which is forwarding) and a set of blocked ports, except for self-looping ports. The uplink group provides an alternate path in case the currently forwarding link fails.
    BackboneFast is initiated when a root port or blocked port on a switch receives inferior BPDUs from its designated bridge. An inferior BPDU identifies one switch as both the root bridge and the designated bridge. When a switch receives an inferior BPDU, it indicates that a link to which the switch is not directly connected (an indirect link) has failed (that is, the designated bridge has lost its connection to the root bridge). Under normal spanning-tree rules, the switch ignores inferior BPDUs for the configured maximum aging time, as specified by the agingtime variable of the set spantree maxage command.
    The switch tries to determine if it has an alternate path to the root bridge. If the inferior BPDU arrives on a blocked port, the root port and other blocked ports on the switch become alternate paths to the root bridge. (Self-looped ports are not considered alternate paths to the root bridge.) If the inferior BPDU arrives on the root port, all blocked ports become alternate paths to the root bridge. If the inferior BPDU arrives on the root port and there are no blocked ports, the switch assumes that it has lost connectivity to the root bridge, causes the maximum aging time on the root to expire, and becomes the root switch according to normal spanning-tree rules.
    If the switch has alternate paths to the root bridge, it uses these alternate paths to transmit a new kind of PDU called the Root Link Query PDU. The switch sends the Root Link Query PDU out all alternate paths to the root bridge. If the switch determines that it still has an alternate path to the root, it causes the maximum aging time on the ports on which it received the inferior BPDU to expire. If all the alternate paths to the root bridge indicate that the switch has lost connectivity to the root bridge, the switch causes the maximum aging times on the ports on which it received an inferior BPDU to expire. If one or more alternate paths can still connect to the root bridge, the switch makes all ports on which it received an inferior BPDU its designated ports and moves them out of the blocking state (if they were in blocking state), through the listening and learning states, and into the forwarding state.

    QUESTION 19
    As a network administrator, can you tell me what the root guard feature provides in a bridgednetwork?
    A.    It ensures that BPDUs sent by the root bridge are forwarded in a timely manner
    B.    It enforces the root bridge placement in the network
    C.    It ensures that all ports receiving BPDUs from the root bridge are in the forwarding state.
    D.    It ensures that the bridge is elected as root bridge in the network.
    Answer: B
    Explanation:
    The root guard feature provides a way to enforce the root bridge placement in the network.
    The root guard ensures that the port on which root guard is enabled is the designated port. Normally, root bridge ports are all designated ports, unless two or more ports of the root bridge are connected together. If the bridge receives superior STP Bridge Protocol Data Units (BPDUs) on a root guard?enabled port, root guard moves this port to a root?inconsistent STP state. This root?inconsistent state is effectively equal to a listening
    state. No traffic is forwarded across this port. In this way, the root guard enforces the position of the root bridge.

    QUESTION 20
    Refer to the following descriptions, which three are true about Cisco spanning-tree features? (Choose three.)
    A.    RPVST+ converges faster than RSTP during a topology change.
    B.    STP BPDUs are relayed by all non-root bridges and RSTP BPDUs are generated by each bridge.
    C.    RSTP can only achieve rapid transition to Forwarding on edge ports and on point-to-point links.
    D.    RPVST+ and RSTP are both based upon the IEEE 802.1w specification.
    Answer: BCD
    Explanation:
    PVST+ is per-VLAN spanning tree (which is the default for most cisco switches).
    It means that you will run an spanning-tree instance per VLAN.
    This is useful when you need different layer 2 behaviors per VLAN, for example you can have different root bridge on different VLANs (so that spanning tree does not have to run as a whole on the layer 2 domain, but can run a different instance per-VLAN)
    RSTP is rapid STP.
    It is an enhancement to STP.
    RSTP does not work with timers as regular STP (which takes up to 30-50 seconds to converge due to the transtion to all its states)
    Regular STP can use port-fast for ports not connected to other switches, but all ports connected to other switches need to transition from blocking to listening, learning and finally forwarding.
    RSTP optimizes this by using P2P lilnks and taking up to only 2 seconds to converge.
    RPVST+
    Is basically when you mix the two above.
    You have an instance of rapid STP running per VLAN.
    Also, some use MST which is another variance of STP which can group several VLANs to be part of a single MST region (and behave like RSTP inside that region).
    MST is useful because if you have 1000 VLANs, normally you don’t need to have 1000 STP/RSTP instances!!
    You can instead have one instance with VLAN 1-500 and another instance with VLANs 501-1000 (just to give you an example)

    134 Total Views 1 Views Today

    Topics: Cisco, Exam | Comments Off on CCIE R&S 350-001 Q&As – Implement Spanning Tree Protocol (STP)(16-20)

    Tagged with:

    Comments are closed.