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OSPF Database unstable?

‎07-04-2015 08:53 AM

Hello Experts

 

I have 25 routers in one area and I can observe that OSPF database is keep changing. What could be the possible cause of this? How can I troublehoot and fix this.

5 REPLIES 5
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Re: OSPF Database unstable?

‎07-06-2015 07:14 AM

Some change would be expected as events happen.  How often can be a concern.  

 

Start with one box and move from there.  Where are you observing the OSPF database changing?  Can you pinpoint from the database changes which router is making the changes?    

 

Are the adjacency forming?  If not, what state are they getting to?  (show ip ospf neigh detail) 

Do you have traceoptions turned on?  

 

set protocols ospf area 0 traceoptions file OSPF

set protocols ospf area 0 traceoptions flag all

commit

show log OSPF

 

What does the log say?  

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Re: OSPF Database unstable?

‎07-07-2015 09:14 PM

Thanks. I am wondering how I could know which router is causing the issue? Can you please help me in this

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Re: OSPF Database unstable?

‎07-07-2015 10:53 PM
If there is a pattern in the database changes that you are seeing. For eg; particular routes which may be changing then you might be able to narrow down the router from where these changes may be getting propagated.
Shailesh
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If this solution worked for you please flag my post as an "Accepted Solution" so others can benefit..]
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Re: OSPF Database unstable?

‎07-07-2015 10:56 PM

Hello ,

 

The OSPF database in an area will only change is there is any change in routing or connected routes  ( Based on DHCP  IPs changing  etc )  . So amoung the 25 routers in the area , are you sure that the connected /static routes are not changed  or any new routes are introuduced . If not , lets take a snapshot of the OSPF database and compare them manually to check if there is any change in routing .

 

> show ospf database

 

If still cannot find them ,  lets see if there is any change seen  in traceoptions  .

 

Do you see any impact in these route database change or traffic is not impacted ?  Check for any OSPF flaps .


Thanks,
Sam

Please Mark My Solution Accepted if it Helped, Kudos are Appreciated too .....
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Re: OSPF Database unstable?

‎07-08-2015 06:46 AM

hi,

 

why you claim database is changing and it's a problem  (and not normal refresh) ? What do you look at ?

In case of Junos LSA refresh time is 50 minutes. 

 

First, I would look at show ospf database output to identify LSAs changing frequently. Please look at increasing sequence numbers and/or Age close to 3600s (fresh LSA). This way you will discover the router(s) making your OSPF unstable.

 

jtb

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