Help with OSPF through MPLS/BGP

[burleyman]

Attached is a network diagram.

I want to setup OSPF throughout and also advertise a default route. The ISP that provides private MPLS runs BGP and will redistribute all OSPF routes to the PE routers (PE1, PE2, PE3, and PE4). I cannot configure the PE routers but will configure the core switches and the ASA1.  

I don’t have an issue configuring OSPF but I am unsure on the AREA 0 through MPLS/BGP.

Here is the OPSF configuration I was going to put in place. Anything I missed or don't need or do differently?

Site 1 core switch

Router ospf 1

Network 10.10.0.0 255.255.255.0 area 0

Network 10.20.0.0 255.255.255.0 area 0

Network 10.30.0.0 255.255.255.0 area 0

redistribute static subnets

redistribute connected subnets

**************************************

Site 2 core switch

Router ospf 1

Network 192.168.32.0 255.255.255.0 area 0

Network 192.168.33.0 255.255.255.0 area 0

Network 192.168.132.0 255.255.255.0 area 0

redistribute static subnets

redistribute connected subnets

**************************************

Site 3 core switch

Router ospf 1

Network 192.168.10.0 255.255.255.0 area 0

Network 192.168.11.0 255.255.255.0 area 0

Network 192.168.110.0 255.255.255.0 area 0

redistribute static subnets

redistribute connected subnets

**************************************

Co-Lo Site ASA1

Route outside 0.0.0.0 0.0.0.0 50.50.100.102 1

Router ospf 1

Network 192.168.36.0 255.255.255.0 area 0

Network 50.50.100.100 255.255.255.252 area 0

Default-information originate metric 30 metric-type 1

redistribute static subnets

redistribute connected subnets

**************************************

[Sunil Bhadauria]

I understand that OSPF to BGP and BGP to OSPF redistribution will happen on all PE routers .

So ,with your requirements I do not see any issues with the configuration , other then below one point :

If you are anyways injecting default route in ospf domain from Co-Lo site , so all other sites unknown destination traffic will anyways follow last resort to Co-Lo ASA , do we still need to redistribute connected / static ?

HTH 

Regards
Sunil Bhadauria

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[burleyman]

Thanks for your help.

Yes I guess you are correct about the redistribute connected and static.

Thanks again,

Mike

[burleyman]

I do actually have a question, would the routes show up as external ospf routes because they are actually multiple area 0's because they are separated by the MPLS/BGP network?

Mike

[Sunil Bhadauria]

Hello ,

yes , to other sites routes will be type 5 ( as they will be recieving via redistribution in OSPF).

Regards

Sunil Bhadauria 

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[burleyman]

Ok that should not be a problem.

Now another question.

I want to also redistribute routes for some Site to Site VPN connections.

on the ASA at the Co-Lo I was going to add this...

Crypto map name_of_crypto_map 10 set reverse-route

This will put the route in the routing table as a static route and should get redistributed to all sites if I also add this to the OSPF config

redistribute static subnets

or would I need to add this also or instead?

redistribute connected subnets

[Sunil Bhadauria]

Hello ,

If considered command is going add a static route in ASA routing table and we need these routes to all other sites then right command would be :

Redistribute static subnets 

But still considering you will anyway inject default route in OSPF domain from ASA ,which will set last resort in all site's routes to go to Co-Lo site , do we still need any other route to be injecting from Co-Lo site to OSPF domain ?

Regards

Sunil Bhadauria

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[burleyman]

Yes I see your point. Looks like I was over thinking the setup.

Thanks for your help.

Mike