Type-5 Default Route vs Summary Default Route in NSSA

Hi all,

I have a router connected to Area 0 and Area 3 NSSA

This router receive 2 default route:

Route via Area 3:

O*IA 0.0.0.0/0 [110/14] via 172.20.1.1, 01:04:19, GigabitEthernet0/2

router# sh ip ospf database summary 0.0.0.0

          OSPF Router with ID (1.1.1.1) (Process ID 1)

                Summary Net Link States (Area 3)

  LS age: 21
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 0.0.0.0 (summary Network Number)
  Advertising Router: 10.16.255.5
  LS Seq Number: 800000A6
  Checksum: 0xF47C
  Length: 28
  Network Mask: /0
        MTID: 0 Metric: 1

  Routing Bit Set on this LSA in topology Base with MTID 0
  LS age: 256
  Options: (No TOS-capability, DC, Upward)
  LS Type: Summary Links(Network)
  Link State ID: 0.0.0.0 (summary Network Number)
  Advertising Router: 10.16.255.6
  LS Seq Number: 800000A5
  Checksum: 0xF080
  Length: 28
  Network Mask: /0
        MTID: 0 Metric: 1

Route via Area 0

O*E2 0.0.0.0/0 [110/20] via 10.16.0.1, 00:00:01, Tunnel1

            OSPF Router with ID (1.1.1.1) (Process ID 1)

                Type-5 AS External Link States

  LS age: 1130
  Options: (No TOS-capability, DC)
  LS Type: AS External Link
  Link State ID: 0.0.0.0 (External Network Number )
  Advertising Router: 10.16.255.5
  LS Seq Number: 8000000E
  Checksum: 0xCBA4
  Length: 36
  Network Mask: /0
        Metric Type: 2 (Larger than any link state path)
        MTID: 0
        Metric: 20
        Forward Address: 10.18.3.227
        External Route Tag: 1

  Routing Bit Set on this LSA in topology Base with MTID 0
  LS age: 313
  Options: (No TOS-capability, DC)
  LS Type: AS External Link
  Link State ID: 0.0.0.0 (External Network Number )
  Advertising Router: 10.16.255.6
  LS Seq Number: 80000001
  Checksum: 0xFA84
  Length: 36
  Network Mask: /0
        Metric Type: 2 (Larger than any link state path)
        MTID: 0
        Metric: 20
        Forward Address: 0.0.0.0
        External Route Tag: 1

The Router prefer O*E2 route over O*IA route.

Why is it so? I think it should prefer O*IA over O*E2

Can you help me explain this?

Thank you,

NP

Blogs and organic groups at http://www.ccie.net
Received on Wed Aug 24 2011 - 22:57:41 ART