OSPF and its use of Multicast

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When it comes to OSPF and its use of multicast, am I correct in believing that IGMP forwarding and an IGMP querier is still required within the local segment?



My understanding would be without this, the frames would be treated as a broadcast and sent to everyone. Therefore removing the benefit of using multicast.



Based on this is there any mechanism for it to fall back to unicast, to prevent the above. Apologies if my understanding here is way off : )






ospf multicast igmp







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    up vote
    3
    down vote

    favorite












    When it comes to OSPF and its use of multicast, am I correct in believing that IGMP forwarding and an IGMP querier is still required within the local segment?



    My understanding would be without this, the frames would be treated as a broadcast and sent to everyone. Therefore removing the benefit of using multicast.



    Based on this is there any mechanism for it to fall back to unicast, to prevent the above. Apologies if my understanding here is way off : )






    ospf multicast igmp







    share|improve this question

























      up vote
      3
      down vote

      favorite









      up vote
      3
      down vote

      favorite











      When it comes to OSPF and its use of multicast, am I correct in believing that IGMP forwarding and an IGMP querier is still required within the local segment?



      My understanding would be without this, the frames would be treated as a broadcast and sent to everyone. Therefore removing the benefit of using multicast.



      Based on this is there any mechanism for it to fall back to unicast, to prevent the above. Apologies if my understanding here is way off : )






      ospf multicast igmp







      share|improve this question















      When it comes to OSPF and its use of multicast, am I correct in believing that IGMP forwarding and an IGMP querier is still required within the local segment?



      My understanding would be without this, the frames would be treated as a broadcast and sent to everyone. Therefore removing the benefit of using multicast.



      Based on this is there any mechanism for it to fall back to unicast, to prevent the above. Apologies if my understanding here is way off : )






      ospf multicast igmp




      ospf multicast igmp






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      share|improve this question













      share|improve this question




      share|improve this question








      edited 1 hour ago









      Ron Maupin♦

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      59k1058106










      asked 1 hour ago









      rick3d

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          The benefit of multicast is that hosts not subscribing to the multicast group ignore frames they receive that are sent to the multicast group. With broadcast, they cannot ignore the frames.



          The OSPF multicast group is a link-local multicast that gets sent to every switch interface, even with IGMP snooping enabled on the switch. OSPF only uses multicast on broadcast networks, and it is necessary in order to use DR and BDR, which are only on broadcast networks. For point-to-point links, OSPF uses unicast, and for non-broadcast networks you use the neighbor statement and it uses unicast.






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            The benefit of multicast is that hosts not subscribing to the multicast group ignore frames they receive that are sent to the multicast group. With broadcast, they cannot ignore the frames.



            The OSPF multicast group is a link-local multicast that gets sent to every switch interface, even with IGMP snooping enabled on the switch. OSPF only uses multicast on broadcast networks, and it is necessary in order to use DR and BDR, which are only on broadcast networks. For point-to-point links, OSPF uses unicast, and for non-broadcast networks you use the neighbor statement and it uses unicast.






            share|improve this answer


























              up vote
              3
              down vote













              The benefit of multicast is that hosts not subscribing to the multicast group ignore frames they receive that are sent to the multicast group. With broadcast, they cannot ignore the frames.



              The OSPF multicast group is a link-local multicast that gets sent to every switch interface, even with IGMP snooping enabled on the switch. OSPF only uses multicast on broadcast networks, and it is necessary in order to use DR and BDR, which are only on broadcast networks. For point-to-point links, OSPF uses unicast, and for non-broadcast networks you use the neighbor statement and it uses unicast.






              share|improve this answer
























                up vote
                3
                down vote










                up vote
                3
                down vote









                The benefit of multicast is that hosts not subscribing to the multicast group ignore frames they receive that are sent to the multicast group. With broadcast, they cannot ignore the frames.



                The OSPF multicast group is a link-local multicast that gets sent to every switch interface, even with IGMP snooping enabled on the switch. OSPF only uses multicast on broadcast networks, and it is necessary in order to use DR and BDR, which are only on broadcast networks. For point-to-point links, OSPF uses unicast, and for non-broadcast networks you use the neighbor statement and it uses unicast.






                share|improve this answer














                The benefit of multicast is that hosts not subscribing to the multicast group ignore frames they receive that are sent to the multicast group. With broadcast, they cannot ignore the frames.



                The OSPF multicast group is a link-local multicast that gets sent to every switch interface, even with IGMP snooping enabled on the switch. OSPF only uses multicast on broadcast networks, and it is necessary in order to use DR and BDR, which are only on broadcast networks. For point-to-point links, OSPF uses unicast, and for non-broadcast networks you use the neighbor statement and it uses unicast.







                share|improve this answer














                share|improve this answer



                share|improve this answer








                edited 1 hour ago

























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