routing issue

[Tareq Emad Al Asfoor]

Hi ,

I'm working on OSPF with totally NSSA , In my network i have 4 routers connected with the Main router with Area 0 and connected to cloud network with Area 10, And the ( area 10 nssa ) enabled in all routers in the cloud and ( area 10 nssa no-summary  ) enabled in the ABR routers ( i.e 1 , 2 ,3 , 4) .. So now each one from these ABR will consider the default getaway for the network area 10 .. So how i can give priority for these ABR ? cuz if we assume the connection between router  (1 & A ) become down. The router 1 will stay consider itself the default gateway for the area even the link down between it and router A and this will cause outage cuz there isn't any way to go from router 1 to core router A .. So is there any way to solve this issue .. Thanks in advance   

[Stuart Gall]

Are you sure this configuration is legal for NSSA ?

You have multiple connections to area 0 so I would have thought that it can't be a stub area.

NSSA allows you to inject external routes I don't think it allows multiple connections to area 0.

If you want to set weights it should not be a stub area.

If you want route summarisation you could use area range instead of making it a NSSA.

[Tareq Emad Al Asfoor]

Thanks, Yeah i need to reduce the routing table inside the area 10 .. so i had to enable the NSSA ..

[Reza Sharifi]

Hi,

If the link between 1&A goes down than r1 will stop advertising the default route to area 10 since it does not have any interface in area 0. If r1 has a loopback interface, it needs to be in area 10 for this to work.

HTH

[Tareq Emad Al Asfoor]

Thanks for ur relay .. What about multiple ABR that connecting to the area 0 .. Is there any priority will be ?  in case the traffic come from A to area 10 .. Thanks in advance 

[Reza Sharifi · Accepted solution]

When multiple ABRs connect NSSA to area0, the router that has the highest router- id will do the translation between type-7 and type-5.

HTH

[Tareq Emad Al Asfoor]

Yes, That's right .. But let we assume the router 1 has the higher router-id .. and the link down between router 1 and A .. .. What will happen in this case .. Thanks in advance