We're Sorry, Full Content Access is for Members Only...

If you like to keep on reading, Become a Member Now! Here is Why:

  • Learn any CCNA, CCNP and CCIE R&S Topic. Explained As Simple As Possible.
  • Try for Just $1. The Best Dollar You've Ever Spent on Your Cisco Career!
  • Full Access to our 617 Lessons. More Lessons Added Every Week!
  • Content created by Rene Molenaar (CCIE #41726)


374 New Members signed up the last 30 days!


100% Satisfaction Guaranteed!
You may cancel your monthly membership at any time.
No Questions Asked!

Tags: ,

Forum Replies

  1. When we need Point to multipoint and Point to multi point non- boradcast

  2. This will depend on the underlying Frame-Relay network. When broadcasting is disabled you will have to use the “non-broadcast” network types.

  3. Hi Renee
    “There are a couple of things that you need to be aware of:
    No Automatic neighbor discovery so you need to configure OSPF neighbors yourself!
    No DR/BDR election since OSPF sees the network as a collection of point-to-point links.
    Only a single IP subnet is used in the topology above.”
    Seems to me I have to commit them to memory.
    I have to say them out loud day in and day out like a mantra.
    I am asking whether or not there is a rhyme or reason to help me memorize or understand them.
    In case of PMNB (point to multipoint nonbroadcast) DLCI’s are not configured?

  4. Hi Lee,

    I don’t have a rhyme but there’s some logic to these OSPF network types:

    Only broadcast and non-broadcast require a DR/BDR election since OSPF sees these network types as “multi-access”. Everything with “point” in it is seen as a collection of point-to-point links so there is no DR/BDR election.

    Everything with “non-broadcast” requires you to configure neighbors since OSPF won’t be able to find them by itself.

    Only with point-to-point we use a subnet for each PVC, all other OSPF network types usually have a single IP subnet.

    Still some memorization to do but if you understand the logic, it will be easier to remember :slight_smile:

    Configuring DLCIs doesn’t have anything to do with OSPF or its network types but when you configure frame-relay, you always need DLCIs…maybe you get one from the frame-relay switch or you have to do it yourself.


20 more replies! Ask a question or join the discussion by visiting our Community Forum