OSPF Network Types

OSPF Network Types
OSPF’s functionality is different across several different network topology types. They are mentioning below

Broadcast Multi-Access – indicates a topology where broadcast occurs.
        •   OSPF will elect DRs and BDRs.
        •   Traffic to DRs and BDRs is multicast to 224.0.0.6. Traffic from DRs and BDRs to other routers is multicast to 224.0.0.5.
        •   Neighbors do not need to be manually specified.
        •   Examples Ethernet

Point-to-Point – indicates a topology where two routers are directly connected.
        • No DRs and BDRs.
        •   All OSPF traffic is multicast to 224.0.0.5.
        •   Neighbors do not need to be manually specified.

Point-to-Multipoint – indicates a topology where one interface can connect to multiple destinations. Each connection between a source and destination is treated as a point-to-point link.
        •    OSPF will not elect DRs and BDRs.
        •   All OSPF traffic is multicast to 224.0.0.5.
        •   Neighbors do not need to be manually specified.

Non-broadcast Multi-access Network (NBMA) – indicates a topology where one interface can connect to multiple destinations; however, broadcasts cannot be sent across a NBMA network.
        •   An example would be Frame Relay.
        •   OSPF will elect DRs and BDRs.
        •   OSPF neighbors must be manually defined, thus All OSPF traffic is unicast instead of multicast. 

Remember: On non-broadcast networks, neighbors must be manually specified, as multicast Hello’s are not allowed.

6 comments:

  1. Are you a human or God ?
    very nicely explained mate !

    Mark.

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    Replies
    1. Hi thanks, its simple and nice

      Delete
  2. Hi, its very helpful notes...Thanks a lot

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  3. I always used to get confused with these network types in OSPF. You made it past. Very beautifully explained. Thanks.

    ReplyDelete
  4. great note, got me up to date

    ReplyDelete