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Forum Replies

  1. Hi Rene,
    what is the default network type for DMVPN tunnel?

    If it is point-to-point, we must change it and become mandatory to change it?

  2. Mahmoud,
    You are exactly right. The default network type of a DMVPN tunnel is Point-to-Point.

    One of the rules of a P2P interface is there can be at most 1 OSPF neighbor. With the Hub’s tunnel interface, however, the OSPF process hears Hello messages from numerous different neighbors’ OSPF processes. This causes the Hub’s OSPF process to churn over and over, throwing out the previously formed Exstart relationship to form a new neighborship with the most recently received Hello. When this happens, you will see these messages on the Hub over and over again fo

    ... Continue reading in our forum

  3. Hey There,

    is it really required to change the OSPF priority to 0 on the spokes in case you go for OSPF network type Broadcast?
    (if i recall it right with DMVPN Ph2 you should have spoke-to-spoke direct connectivity and if this is true then it should be technically possible for the spokes to be elected as DR/BDR )

    Regards,
    Salvatore.

  4. Hello Salvatore

    Yes you are correct that for Phase 2 with a broadcast network type, there is direct spoke-to-spoke connectivity. However, this direct connectivity is achieved AFTER the initial communication occurs with the HUB. When a spoke router wants to reach another spoke, it will send an NHRP resolution request to the hub to find the NBMA IP address of the other spoke. This means that initial connectivity must be made with the hub router.

    Additionally, in order to achieve this direct spoke-to-spoke connectivity, you need two things:

    * Spoke routers need

    ... Continue reading in our forum

  5. Ciao Lazaros,

    thanks for your detailed description,

    if i understood it right, it seems to be a matter of priorities:
    before the spoke-to-spoke communication can work I should have hub & spoke reachability which means that, in case I decide to use OSPF, the DR/BDR election it’s a prerequisite for the spoke-to-spoke communication to be established

    Thanks,
    Salvatore.

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