Which two elements contribute to the bridge ID when configuring RSTP?

Which two elements contribute to the bridge ID when configuring RSTP? (Choose 2)

A.
designated MAC address

B.
bridge priority

C.
extended system ID

D.
root ID

E.
bridge address

Explanation:
The bridge ID consists of a configurable bridge priority and the MAC address of the bridge.

Reference:
http://www.juniper.net/techpubs/software/junos/junos95/swconfig-layer-2/conf-stp.html#conf- bridge-priority

Discussion

9 Responses to “Which two elements contribute to the bridge ID when configuring RSTP?”

  1. nikish bhat says:

    I got the same ques in JNCIS but it it was sking for three options.Any guess what can be the third option?

  2. neo says:

    The correct answers are already given. But if it asks for third answer then it most likely answer E.

  3. MisterK says:

    Designated Mac address is wrong : this is the mac address of the designated bridge.
    The Answer should be:
    1-Bridge priority
    2-Bridge address (Mean bridge Mac address)
    3-Extended system ID (affect the bridge priority ) in case needed

  4. jon says:

    B y E

    The root bridge for each STP instance is determined by the bridge ID. The bridge ID consists of a configurable bridge priority and the MAC address of the bridge.

  5. Yassine says:

    Bridge ID:
    1. bridge priority = [Priority + Extended system]
    2. Bridge Address (MAC Adress)

    So the answer should be:
    –> Bridge Address
    –> Bridge priority
    (and Extended system)

    ==> B & E

  6. warrior00 says:

    This question is about _configuration_ of RSTP.

    #set protocols rstp bridge-priority …

    #set protocols rstp extended-system-id …

    So, B & C.

    bridge MAC address is not “contributing in configuration”!

  7. Ahmed Abd Allah says:

    Realy not obvious Question.

    Bridge ID = Priority + Bridge MAC address + Extended System ID.

  8. The bridge ID consists of a configurable bridge priority and the MAC address of the bridge.. this say in the link http://www.juniper.net/techpubs/software/junos/junos95/swconfig-layer-2/conf-stp.html#conf- bridge-priority

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