nssa convertion

[bluesea2010]

Hi,

I have the below topolgy . Now  I want to convert area 50. How  can I  minimize downtime .  for example if I am  changing switch3 to  nssa other  ASBR  (vios4 ) neighbourship should not go down  )

The default route injected  from the area 0 , If I convert to ASBR TO ABR ( vIOS 2 AND 4 ) to ABR ( area 50 to area 0 )  what should I do for default route 

Thanks

Any solution 

Thanks

[MHM Cisco World]

.

[balaji.bandi]

Depends how you have configured ?

When you convert the area to different area, the OSPF convergence take place that is expected (there is no alternative for that) you expect that time of loss.

If you Like to build other way (not suggested but can be possible) 

Build another Interface and make a right area - and shutdown the old area. (but careful in production - in the Lab for testing its ok).

how the default route can be done in other area below example help you :

https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13692-21.html

[Joseph W. Doherty]

For minimal down time, you create a file on each device with that device's needed configuration changes, and have a device script load the changes at the same time as all your other devices.  Ideally, area will be down for just a few seconds.

[bluesea2010]

Hi,

The moment I change area 50 to NSSA, all other router neighborships will go down, including section 1 and section 2. I am using loopback as in-band management. There are approximately 50 routers directly connected to VIOS4, as shown in the example diagram. So, I am considering changing VIOS4 to an ABR by adding it to area 0, and then changing section 1 to area 60 and converting it to NSSA. This way, the area 50 will remain unaffected. Are there any pros and cons to this approach?"

Thanks

[Joseph W. Doherty]

If I correctly understand your current OSPF topology and what you propose I don't believe the net impact will be impacted.