Company ABC closes a deal with a Partner Company that requires redundant network paths between the two networks. This requirement is met by enabling 2 connections: one FastEthernet between R1 and R5 and one Serial link between R2 and R6.

Static routes are configured on R1 and R2 for the 2 subnets in partner's network ( and and they are redistributed into the OSPF Area 0:


Unfortunately, the network administrator is not happy with the OSPF best path performed on the company router R3 for those external routes.
As displayed above, R3 prefers the path via R4 -> then R2 -> then Serial link to reach the Partner's network.

  1 80 msec 48 msec 28 msec
  2 64 msec 40 msec 68 msec
  3 32 msec 56 msec 64 msec
  4 124 msec *  148 msec
R3#sh ip route
Routing entry for
  Known via "ospf 1", distance 110, metric 20, type extern 2, forward metric 2
  Last update from on FastEthernet0/1, 00:06:56 ago
  Routing Descriptor Blocks:
  *, from, 00:06:56 ago, via FastEthernet0/1
      Route metric is 20, traffic share count is 1

Why is it so? Is there a problem with OSPF or the selected path is really the shortest/correct one ?

- there was no manipulation of OSPF costs !!
- don't worry about return traffic: static routing for network was configured on Partner devices !

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