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STP Questions 4

November 21st, 2018 in SWITCH 300-115 Go to comments

Question 1


The port-priority of all STP ports is 128 so we need to use a lower value (higher priority) so that this port can become root bridge. But this answer is not totally correct (it only the best choice in this question) as the increment of port priority is 32, which means only values 0, 32, 64, 96, 128, 160, 192, and 224 are acceptable. All other values are rejected.

Question 2


When Spanning Tree Protocol learns about the network it looks at a Port-Channel interface as a single interface so it will use the port channel for forwarding.

Question 3

Question 4


Change to “lower value” means “higher priority” so the secondary link would be preferred over primary link.

Question 5

Question 6

Question 7

Question 8

Question 9


There are no “no spanning-tree pvst” or “no spanning-tree mst” commands. They should be “no spanning-tree mode pvst” or “no spanning-tree mode mst” so answer A is the best option left.

  1. Due_Diligence
    December 16th, 2018


    The second answer (D) given for Q5 is not a valid command. The priority needs to be a numeric value in increments of 4096

    D. DSW1(config)#spanning-tree vlan 10 priority *root*

  2. sdc
    December 19th, 2018


    Another valid syntax for D would be this:

    DSW1(config)#spanning-tree vlan 10 root primary

  3. Anonymous
    January 26th, 2019

    for question 5, how is A correct?

    A priority of 61440 is less than DSW2’s 24576

  4. LMV
    April 20th, 2019

    I think A is not the right answer, should be 4096 no 61440 in the last section STP 3 the same question answer that.

  5. LuciasDA
    May 31st, 2019

    Could you review this question please, something is not right. Similar issue with STP questions 3 Q5.
    Question 5
    A. Ensures that DSW2 will not be root bridge as the priority is at maximum.
    B. Is incorrect as the 4066 is not a multiple of 4096
    C. Would do the opposite of whats desired
    D. This command doesn’t exist? “Root Primary” would be correct
    E. This command would have no effect on election, but would ensure that the port has best priority.

  6. CP
    August 25th, 2019

    Q5 is correct.
    Here we are changing the Bridge Priority of DSW2 and not DSW1. 61440 is the highest bridge priority you can set. This will make sure that DSW1 becomes the root bridge for Vlan 10.
    Although there seems to be some typo in option D, as it needs to be root primary and priority root

  7. Dmytro
    October 5th, 2019

    Q5 is NOT correct because we don’t have a command “spanning-tree vlan 10 priority root”, we have a command:
    spanning-tree vlan 10 root primary

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