09-05-2013 09:54 AM - edited 03-07-2019 03:19 PM
Hi,
I have a pair of Nexus 7k configured as ABRs. Problem is that one of them seems to not flood LSA received from a NSSA area into backbone area.
Topology:
area 0
| |
abr1------abr2
| |
| nssa |
| |
agg1-----agg2
Devices to which these N7ks connect to via nssa area are configured identically.
Both agg1 and agg2 redistribute connected routes, which abr1 and abr2 flood into the backbone.
And while agg2 works fine, agg1 doesn't.
When running "show ip ospf database external self-originated" command on abr1 shows nothing, while the second box shows expected results (links receivced from agg2)
Configuration is very simple. no filtering,distribute-list, route-maps etc..
Anyone can tell what might be the reason for such behaviour?
best regards
Kuba
Solved! Go to Solution.
09-05-2013 01:53 PM
Hi Kuba,
the type-7 to type-5 translation is only done by the ABR with the highest RID if multiple NSSABRs exist:
R1#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
2.2.2.2 0 FULL/ - 00:00:31 172.16.12.2 Serial0/1
3.3.3.3 0 FULL/ - 00:00:31 172.16.13.3 Serial0/0
R1#show ip ospf database external self-originate
OSPF Router with ID (1.1.1.1) (Process ID 1)
R1#
R1(config-router)#router-id 10.10.10.10
R1#clear ip ospf proc
Reset ALL OSPF processes? [no]: yes
R1#show ip ospf database external self-originate
OSPF Router with ID (10.10.10.10) (Process ID 1)
Type-5 AS External Link States
LS age: 0
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 192.168.2.0 (External Network Number )
Advertising Router: 10.10.10.10
LS Seq Number: 80000001
Checksum: 0x6F51
Length: 36
Network Mask: /24
Metric Type: 1 (Comparable directly to link state metric)
TOS: 0
Metric: 20
Forward Address: 172.16.13.3
External Route Tag: 0
http://blog.ine.com/2008/11/24/new-ospf-updates-teaser/
Hope that helps
Rolf
09-05-2013 01:53 PM
Hi Kuba,
the type-7 to type-5 translation is only done by the ABR with the highest RID if multiple NSSABRs exist:
R1#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
2.2.2.2 0 FULL/ - 00:00:31 172.16.12.2 Serial0/1
3.3.3.3 0 FULL/ - 00:00:31 172.16.13.3 Serial0/0
R1#show ip ospf database external self-originate
OSPF Router with ID (1.1.1.1) (Process ID 1)
R1#
R1(config-router)#router-id 10.10.10.10
R1#clear ip ospf proc
Reset ALL OSPF processes? [no]: yes
R1#show ip ospf database external self-originate
OSPF Router with ID (10.10.10.10) (Process ID 1)
Type-5 AS External Link States
LS age: 0
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 192.168.2.0 (External Network Number )
Advertising Router: 10.10.10.10
LS Seq Number: 80000001
Checksum: 0x6F51
Length: 36
Network Mask: /24
Metric Type: 1 (Comparable directly to link state metric)
TOS: 0
Metric: 20
Forward Address: 172.16.13.3
External Route Tag: 0
http://blog.ine.com/2008/11/24/new-ospf-updates-teaser/
Hope that helps
Rolf
09-05-2013 03:11 PM
I get it. Thank You.
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