ospf capability vrf-lite

Answered Question
Nov 2nd, 2009
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hi guys

can someone give me a good example of the ospf capability vrf-lie

i understand the downbit and domainid concept but i cant find an example show the when i can use this command to help or add to a network to establish connectivity


thank you

Correct Answer by Peter Paluch about 7 years 8 months ago

Hello Marwan,


Assume that you as a customer of a MPLS VPN are yourself using a VRF. Your CE interface heading towards a PE router is already placed in some VRF and the OSPF running between your CE and the provider's PE router is also activated in this VRF.


In this situation, the LSAs of type 3, 5 and 7 generated by the PE will have the DN bit set. Because of this, your OSPF instance will ignore them. As a result, your CE router will not learn routes from the PE router though they will be present in your OSPF database.


The capability vrf-lite removes the check for the DN bit and allows your OSPF to consider these LSAs in its SPF calculation.


So in short, the capability vrf-lite effects can be seen in cases where you as a VRF-enabled router receive redistributed routes from another OSPF process that also runs in a VRF and redistributes some networks from BGP.


Best regards,

Peter


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Correct Answer
Peter Paluch Mon, 11/02/2009 - 03:27
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  • Cisco Employee,

Hello Marwan,


Assume that you as a customer of a MPLS VPN are yourself using a VRF. Your CE interface heading towards a PE router is already placed in some VRF and the OSPF running between your CE and the provider's PE router is also activated in this VRF.


In this situation, the LSAs of type 3, 5 and 7 generated by the PE will have the DN bit set. Because of this, your OSPF instance will ignore them. As a result, your CE router will not learn routes from the PE router though they will be present in your OSPF database.


The capability vrf-lite removes the check for the DN bit and allows your OSPF to consider these LSAs in its SPF calculation.


So in short, the capability vrf-lite effects can be seen in cases where you as a VRF-enabled router receive redistributed routes from another OSPF process that also runs in a VRF and redistributes some networks from BGP.


Best regards,

Peter


Marwan ALshawi Mon, 11/16/2009 - 04:28
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thank you :)

i got it

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