Been discussing this with people and reading up, would like people's thoughts on whether or not its worth running IPv6 in a VRF or just let it loose in the global routing table.

Even though presently we use a VRF topology for various reasons, for IPv6 I am strongly on the side of running it natively - resource consumption (thinking of full internet routing tables in IPv6 in a VRF, yech) - no more multiple routing processes per router - lots of our present HW that is not going to go EOL in the next year or two struggles with IPv6 in a VRF (3750, 3560)

For purposes of 'mimicking' VRF separation for areas that require it going to bite the bullet and put firewalls where I need, the only alternative (short of mirroring the present VRF topology) is to go to a nightmare of tunnels and PBRS

I guess the penny dropped when reading about IPv6 on MPLS 6PE.

Thoughts appreciated (especially the ones telling me I'm wrong! its how I learn lol)

  • Upon further research I don't think I have any other option BUT to retain the VRFs as I need to present IPv4 and Ipv6 simultaneously, they can't come out of two different VRFs in the same VLAN/access port. Has anyone ever used the command vrf upgrade-cli? Is there an outage? Cisco.com says no but I am worried more about the VRF commands in BGP, OSPF etc. etc..... gonna lab it up but I can only lab IOS not our IOS-XE or 6500/4500s.... Oct 2, 2013 at 3:14
  • So... what are you asking about? This question seems a bit open-ended. Please look at the FAQ regarding on-topic networkengineering.stackexchange.com/help/on-topic and off-topic networkengineering.stackexchange.com/help/dont-ask Oct 2, 2013 at 10:12
  • There is no outage in vrf upgrade-cli. And depending on platform you could have IPV4 in VRF and IPV6 in Global (but not in 3560/3750 as PBR and VRF are mutually exclusive there). I personally do not feel decision of VRF should be AFI aware, either you need VRF for both or you need it for neither, nor do I share your worry about running IPv6 VRF.
    – ytti
    Oct 2, 2013 at 13:45
  • Running multiple firewalls instead of using VRF sounds quite expensive to me, unless you're multi-context firewalls already.
    – pauska
    Oct 3, 2013 at 20:53
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 8, 2017 at 15:03

1 Answer 1


IPv4 and IPv6 operate as 'ships in the night' as far as routing is concerned, so I see not benefit to separate VRFs with ipv4 in one and ipv6 in another. Also any dual stack hosts would need separate interfaces or separate tagged VLANs to operate dual stack. Now if you are concerned about RAM in the router VRF will not help that, for that concern route summarization or default routing would help there, and that applies to both IPv6 and ipv4

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