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Forum Replies

  1. system says:

    Keep in mind that the physical interface for frame-relay is always non-broadcast.

  2. Hi Gabriel,

    OSPF network broadcast will work but it's normally used for frame-relay point-to-multipoint topologies like in this example. For frame-relay point-to-point it's best to use the point-to-point or point-to-multipoint network type.

    On the other hand, you can make all the OSPF network types work on any given topology...

  3. Hi Jason,

    When configuring frame-relay, we have two options:

    The links above will show you a configuration example for each. The main difference is that point-to-multipoint uses a single subnet for all PVCs while point-to-point uses a different subnet for each PVC.

    Now when it comes to OSPF, this can be confusing yes...here are all network types:

    One of the main differences between broadcast/non-broadcast and the point-to-multipoint network types is the next hop that we use, take a look here:

    OSPF network types IP next hop

    Frame-relay is NBMA but with the correct frame-relay maps, we can "emulate" broadcast traffic so that you can forward multicast/broadcast traffic on the PVCs.


  4. Hi Ahmad,

    They all work so it doesn't matter too much which one you pick.

    The point-to-point or point-to-multipoint network types are probably the easiest to use. You don't require a DR/BDR election so you don't have to worry about setting the correct priority.


  5. Hello Michael.

    I refer to yout @ReneMolenaar’s previous post where he states that [quote=“ReneMolenaar, post:24, topic:921”]
    They all work so it doesn’t matter too much which [network topology] you pick.

    The point-to-point or point-to-multipoint network types are probably the easiest to use. You don’t require a DR/BDR election so you don’t have to worry about setting the correct priority.

    So it really doesn’t matter which network type you choose, as long as they are configured correctly.

    However, keep the following issues in mind:

    • If each area is composed of a point to point connection between routers, you do not require DR/BDRs at all.
    • Secondly if you are creating four areas and these areas connect to each other in a ring topology, then one of these areas will not be directly connected to area 0. You will require either a virtual link (which is not advisable as a permanent solution) or you will need to revise the topology.

    I hope this has been helpful!


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