OSPF Path Selection explained

Hello Samir

Yes, you are correct. I believe a more correct way of stating the overall order of preference of route types for OSPF becomes:

  • Intra-Area Paths (O)
  • Inter-Area Paths (O IA)
  • External Type 1 (E1) Paths / NSSA Type 1 (N1) Paths
  • External Type 2 (E2) Paths / NSSA Type 2 (N2) Paths

Within the same path-type category (like E1/N1 or E2/N2), OSPF will prefer the path with the lower metric. Only when the metric is the same will type E1 be preferred over N1, and type E2 be preferred over N2.

I will let Rene know so he can consider updates to the lesson. Thanks for sharing your thoughts and your experimentation with us!

I hope this has been helpful!

Laz

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