[c-nsp] How the "best" route is selected (OSPF)

[Kristofer Sigurdsson]

Hi guys,

I am a bit lost in a case where my understanding of OSPF seems
to be a bit off.

The scenerio: Same network, learned through two seperate OSPF processes,
same type (I tried external 1 and external 2).  This route is in the
OSPF databases
for both processes.
The only difference is the metric.  It's much higher in one of the
processes, as it's
preferred.

Now, the way I understand it, the route with the lower metric should
always be chosen and put into the routing table.  However, it seems
that the route that's injected first wins.  Even if the other one pops
in only a few minutes later, as long as the first one is valid, it
continues to be the one in the routing table.
If I try to clear the route (clear ip route x.x.x.x), it gets
refreshed...as the same route as before I cleared...

Here's a glimpse of how it looks in the two databases:

router#sh ip ospf 3 database external x.x.x.x

            OSPF Router with ID (y.y.y.y) (Process ID 3)

                Type-5 AS External Link States

  Routing Bit Set on this LSA
  LS age: 108
  Options: (No TOS-capability, DC)
  LS Type: AS External Link
  Link State ID: x.x.x.x (External Network Number )
  Advertising Router: z.z.z.z
  LS Seq Number: 80000001
  Checksum: 0xF67E
  Length: 36
  Network Mask: /24
        Metric Type: 1 (Comparable directly to link state metric)
        TOS: 0
        Metric: 400
        Forward Address: 0.0.0.0
        External Route Tag: 0

rtr3.s24#sh ip ospf 4 database external x.x.x.x

            OSPF Router with ID (v.v.v.v) (Process ID 4)

                Type-5 AS External Link States

  Routing Bit Set on this LSA
  LS age: 112
  Options: (No TOS-capability, DC)
  LS Type: AS External Link
  Link State ID: x.x.x.x (External Network Number )
  Advertising Router: t.t.t.t
  LS Seq Number: 80000001
  Checksum: 0x5D87
  Length: 36
  Network Mask: /24
        Metric Type: 1 (Comparable directly to link state metric)
        TOS: 0
        Metric: 30
        Forward Address: 0.0.0.0
        External Route Tag: 0

>From show ip route:

router#sh ip route x.x.x.x
Routing entry for x.x.x.x/24
  Known via "ospf 3", distance 110, metric 401, type extern 1
  Last update from z.z.z.z on GigabitEthernet1/22, 00:14:01 ago
  Routing Descriptor Blocks:
  * z.z.z.z, from z.z.z.z, 00:14:01 ago, via GigabitEthernet1/22
      Route metric is 401, traffic share count is 1

...now, why is the route with the higher metric in the routing table? 
Is there something I'm missing?

Thanks,
-Kristo