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VRF OSPF Redistribution

CiscoIPMAN
Level 1
Level 1

I know that VRF's make it look like it has its own routing table. One of the benefits I gather is using the same IP space. 

 

If I have a main campus and a remote campus that both want to use the address space of 10.10.10.0/24. Could this be accomplished by using a VRF? 

 

If I use a routing protocol like OSPF could I redistribute the routes so I can access resources in both places? If so how can OSPF tell what 10.10.10.0 network? RD?

 

Is this a common practice?

 

Thanks for the help!

4 Replies 4

Deepak Kumar
VIP Alumni
VIP Alumni

Hi,

If I have a main campus and a remote campus that both want to use the address space of 10.10.10.0/24. Could this be accomplished by using a VRF? 

You, You can use the same address space in two VRF's. But here is some misunderstanding that main campus and remote campus, what are those? If those are VRF name then it is ok and if both are different sites and different router on both locations that it is not a VRF solution.

VRF is basically, used for virtualization a single router's routing table.

 

If I use a routing protocol like OSPF could I redistribute the routes so I can access resources in both places? If so how can OSPF tell what 10.10.10.0 network? RD?

As it is a VRF lite then you can redistribute (leak) OSPF routing protocol database between VRF's but you have to use the BGP routing protocol for making it possible.  As you said that both VRF's having the same subnet then the required solution will not possible due to routing protocol behavior. 

 

 

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!

Deepak,

Thanks for the reply. Yes it would be 2 different sites, so what would be a acceptable solution, like MPLS?

 

If I had 1 switch with 2 SVI with the same IP subnet and each had their own VRF, how could I provide routing to enterprise resources? OSPF or EIGRP would not work?

 

Thank you

Hi,

 Yes it would be 2 different sites, so what would be a acceptable solution, like MPLS?

Ans: If there are two different sites over MPLS and having the same address same and you want to use resources from both sites then there could be a more complex solution as VXLAN / OTV so you can share Layer 2 information but you cant use duplicate Ip address on both sites. It will work the same as a local LAN. This only works if you have Nexus level switches at both sites. 

Another solution is you can perform NATing on both ends as we called Overlapping NAT solution. We need to configure NAT on both locations.

 

If I had 1 switch with 2 SVI with the same IP subnet and each had their own VRF, how could I provide routing to enterprise resources? OSPF or EIGRP would not work?

It will not work as you need, We need again some overlapping NAT solution. Really, I never tried that how it will work. As my understating, you need to extend both subnets to the NATing aware device as the Nexus switch or Router for the same.

 

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!
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