I am learning about OSPF external routes (E2) and I've decided to lab them up. Here is my topology. enter image description here and are just loopbacks configured on the ASBR.

My book states that external Type 2 (E2) routes follow only the redistribution metric (the metric does not increment) and that the metric is the same for every router, which in this case should be 20.

If the metric/cost for the redistributed routes is the same for every router in this OSPF domain, why isn't R5 load balancing the traffic among R3 and R4? Shouldn't it have 2 equal cost paths at this point?

enter image description here

Thank you in advance for your help.

1 Answer 1


You might want to look at the forward metric of the E2 routes. Forward metric reflects the (internal) cost to reach the ASBR where the given E2 routes originate.

Your network diagram makes it clear that R5's possible paths to R1 are not of equal cost/metric, so it will always prefer the link to R4 to send packets towards the external destinations at R1.

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