From: Geert Nijs (Geert.Nijs@simac.be)
Date: Thu Aug 21 2008 - 11:05:23 ART
If neighbor goes down, i would presume all LSA of that router become invalid - instantly - and OSPF should remove them from the database and to a recalculation.
regards,
Geert
________________________________
From: Fahad Khan [fahad.khan@gmail.com]
Sent: 21 August 2008 13:30
To: Geert Nijs
Cc: ccielab@groupstudy.com
Subject: Re: OSPF neighbor down, yet OSPF database is not updated/refreshed ?
For how long you found this behaviour? I mean to say that, may be after a certain period of time,you saw them out of database table. Database table contains LSAs only, may be this has some thing to do with LSA aging time.
On 8/21/08, Geert Nijs <Geert.Nijs@simac.be<mailto:Geert.Nijs@simac.be>> wrote:
Hi all,
I have strange stuff going on in my network. Yesterday, i bounced an interface (shut/no shut) to reset an OSPF neighborship.
However, when the neighbor was down, it seemed OSPF didn't update its database. The routes were still in the OSPF database. I don't understand:
The routes concerned are external redistributed routes:
show ip ospf database
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
10.50.0.0<http://10.50.0.0> 19.16.139.113<http://19.16.139.113> 1421 0x800001EE 0x00E290 401 <<<------------ look at these routes
10.50.0.0<http://10.50.0.0> 19.16.139.114<http://19.16.139.114> 1040 0x8000004D 0x001B2D 400
10.50.32.0<http://10.50.32.0> 19.16.139.113<http://19.16.139.113> 1421 0x800001EE 0x0081D1 401 <<<------------ look at thse routes
10.50.32.0<http://10.50.32.0> 19.16.139.114<http://19.16.139.114> 1040 0x8000004D 0x00B96E 400
sh ip ospf neighbor
19.16.139.113<http://19.16.139.113> 1 FULL/BDR 00:00:19 10.63.14.1<http://10.63.14.1> Vlan997
Then i disable the interface:
%OSPF-5-ADJCHG: Process 1, Nbr 19.16.139.113<http://19.16.139.113> on Vlan997 from FULL to DOWN, Neighbor Down: Dead timer expired
sh ip ospf database
10.50.0.0<http://10.50.0.0> 19.16.139.113<http://19.16.139.113> 1725 0x800001EE 0x00E290 401 <<<-- STILL HERE ???
10.50.0.0<http://10.50.0.0> 19.16.139.114<http://19.16.139.114> 1344 0x8000004D 0x001B2D 400
10.50.32.0<http://10.50.32.0> 19.16.139.113<http://19.16.139.113> 1725 0x800001EE 0x0081D1 401 <<<-- STILL HERE ???
10.50.32.0<http://10.50.32.0> 19.16.139.114<http://19.16.139.114> 1344 0x8000004D 0x00B96E 400
ping 19.16.139.113<http://19.16.139.113>
..... <<-- he is down for sure
Why doesn't the database get updated ? I need the route to be removed and re-inserted/refreshed with an up-to-date tag.
regards,
Geert
CCIE #13729
Details when neighbor is UP:
# sh ip ospf database external 10.50.0.0<http://10.50.0.0>
OSPF Router with ID (192.168.1.1<http://192.168.1.1>) (Process ID 1)
Type-5 AS External Link States
LS age: 1897
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 10.50.0.0<http://10.50.0.0> (External Network Number )
Advertising Router: 19.16.139.113<http://19.16.139.113> <---- this is it
LS Seq Number: 800001EE
Checksum: 0xE290
Length: 36
Network Mask: /19
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 60
Forward Address: 0.0.0.0<http://0.0.0.0>
External Route Tag: 401
Routing Bit Set on this LSA <--- what does this mean ? this is the redundant path route and currently the preferred one. Is there no refresh when "routing bit" not set ?
LS age: 1516
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 10.50.0.0<http://10.50.0.0> (External Network Number )
Advertising Router: 19.16.139.114<http://19.16.139.114> <---redundant path, currently selected (see cost)
LS Seq Number: 8000004D
Checksum: 0x1B2D
Length: 36
Network Mask: /19
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 10
Forward Address: 0.0.0.0<http://0.0.0.0>
External Route Tag: 400 <<<--- i want this tag to update !!
Details when neighbor is DOWN:
# sh ip ospf database external 10.50.0.0<http://10.50.0.0>
OSPF Router with ID (192.168.1.1<http://192.168.1.1>) (Process ID 1)
Type-5 AS External Link States
LS age: 1984
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 10.50.0.0<http://10.50.0.0> (External Network Number )
Advertising Router: 19.16.139.113<http://19.16.139.113> <-------- STILL HERE !
LS Seq Number: 800001EE
Checksum: 0xE290
Length: 36
Network Mask: /19
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 60
Forward Address: 0.0.0.0<http://0.0.0.0>
External Route Tag: 401
Routing Bit Set on this LSA
LS age: 1603
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 10.50.0.0<http://10.50.0.0> (External Network Number )
Advertising Router: 19.16.139.114<http://19.16.139.114>
LS Seq Number: 8000004D
Checksum: 0x1B2D
Length: 36
Network Mask: /19
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 10
Forward Address: 0.0.0.0<http://0.0.0.0>
External Route Tag: 400
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