WB1 6.5~6.6 OSPF Network Point-to-Multipoint & OSPF Network Point-to-Multipoint Non-Broadcast

兩種OSPF Network Point-to-Multipoint (Multicast) & (Non-Broadcast - Unicast) 讓Spoke可以透過Hub Router將學到的路由Next-Hop改成為Hub的IP



6.5 OSPF Network Point-to-Multipoint

R1~R4:

interface Serial0/0/0
  ip ospf 1 area 0
  ip ospf network point-to-multipoint
  frame-relay map ip 155.1.0.5 405 broadcast

R5:

interface Serial0/0/0
  ip ospf 1 area 0
  ip ospf network point-to-multipoint
  frame-relay map ip 155.1.0.1 501 broadcast
  frame-relay map ip 155.1.0.2 502 broadcast
  frame-relay map ip 155.1.0.3 503 broadcast
  frame-relay map ip 155.1.0.4 504 broadcast.


6.6 OSPF Network Point-to-Multipoint Non-Broadcast

R1~R4:

interface Serial0/0/0
  ip ospf 1 area 0
  ip ospf network point-to-multipoint non-broadcast
  frame-relay map ip 155.1.0.5 405

R5:
interface Serial0/0/0
  ip ospf 1 area 0
  ip ospf network point-to-multipoint non-broadcast
  frame-relay map ip 155.1.0.1 501
  frame-relay map ip 155.1.0.2 502
  frame-relay map ip 155.1.0.3 503
  frame-relay map ip 155.1.0.4 504
!
router ospf 1
  neighbor 155.1.0.1
  neighbor 155.1.0.2
  neighbor 155.1.0.3
  neighbor 155.1.0.4

The Non-Broadcast network type means that there will be a DR/BDR election,
and that hellos are exchanged as unicast. In order to unicast OSPF hellos the
neighbor statement needs to be configured under the OSPF process of the DR.
Once the DROTHERs and/or BDR hear the unicast hellos from the DR, they will
automatically respond back with their own unicast hellos. This implies that the
neighbor statement can be configured everywhere, but is only required on the
DR. Once R5 is configured with the neighbor statement the show ip ospf
neighbor output should be checked to verify adjacency.

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OSPF network type

point-to-multipoint non-broadcast is essentially the same as network type point-to-multipoint, with one exception.

Point-to-multipoint network type uses multicast hellos,
Point-to-multipoint non-broadcast uses unicast hellos.

Both do not support the DR/BDR election, automatically update the nexthop value of routes learned on partially meshed networks to the directly connected neighbor, and advertise the network as a set of endpoints instead of a transit network.