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Iam just curious to know whether ipv4 routes can be redistributed to ipv6 address-families. Eg: I have a router for BGP configuration with ipv6 address-family and OSPF in ipv4 with other neighbor. Can I do the redistribution?

          BGP                           OSPF
R1 <---------------------> R2 <---------------------> R3
11::1/64          11::2/64    1.1.1.1/24          1.1.1.2/24 
                                                  Route - 2.0.0.0/8

BGP configs:

R2:

router bgp 100
neighbor 11::2 remote-as 200
address-family ipv6 unicast
neighbor 11::2 activate
redistribute ospf
!

Is it possible for redistribution of ospf ipv4 routes onto BGP ipv6 address-family.

Or If dual-stack is supported, can we do redistribution.

Could anyone please clarify on this.

Appreciate the help.

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    Not sure of the problem you are trying to solve. While the RFC below appears to let you put IPV4 routes from R3 into the IPV4 family BGP table in R1 it will NOT allow IPv6 hosts attached in R1 to reach Iv4 hosts in R3.
    – fredpbaker
    Oct 18 '13 at 11:35
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    @fredpbaker ACK. BGP is just signalling data and does not really care at all if NLRI forgiven AFI/SAFI is transported over another AFI. However, as Fred points out, actual forwarding won't work, as you won't have usable next-hop in the NLRI for that AFI. 6PE/6VPE are special cases and are using IPv4 NH for IPv6 advertisements and in future I'm sure 4PE/4VPE will do the same. But use-case for this would be to give the data to say route analyzer/collector, if you need forwarding you need matching AFI.
    – ytti
    Oct 18 '13 at 13:37
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Yes you can - http://tools.ietf.org/html/rfc5549

However this is quite rare. It's far more common to do it the other way around with v6 nlri advertised over the v4 connection (used by 6PE and 6VPE)

If you're dual-stacked it's far better to simply have a v6 and v4 BGP connection and advertise the correct address families for each

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