Re: [v6ops] draft-smith-v6ops-larger-ipv6-loopback-prefix-04

[Gyan Mishra <[e-mail]>]

Hi Mark

Thanks for responding.

The use case was for BFD continuity test for special use cases or MPLS lsp
ping and now draft for  vxlan BFD, where for IPv4 for continuity test you
have 127/8 loopback but for IPv6 there is only one loopback address ::/128.


For IPv6 we ended up using IPv4 mapped IPv6 addresses for MPLS LSP ping
used to bootstrap to FEC LSP ping to BFD.  So now for new vxlan BFD the
topic came up and again for another draft which now as a standard we are
now planning to use IPv4 mapped IPv6 for BFD continuity test.

That BFD thread brought back the IPv6 RFC 4291 standard that IPv6 only has
one loopback where IPv4 has a /8 worth.

As you stated per RFC 4291, there is supposedly a link local /64 fe80::/64
loopback on the loopback interface which has plenty of space.  I have to
check on a router but I am guessing If that is implemented by all router
vendors following RFC 4291, then that would be an alternative option to
IPv4 mapped IPv6 for BFD continuity tests.

Thanks

Gyan

On Mon, Oct 26, 2020 at 9:22 PM Mark Smith <[e-mail]> wrote:

> Hi Gyan,
>
> Sorry not to get back to you sooner.
>
> On Tue, 20 Oct 2020 at 00:26, Gyan Mishra <[e-mail]> wrote:
> >
> >
> > Hi Mark
> >
> > What ended up happening with this draft
>
> I let it expire, as I didn't think it would be adopted by the WG.
>
> There seemed to be a bit of resistance to it as people said that ULAs
> could be used instead.
>
> The link local prefix is also required on any IPv6 interface, per
> RFC4291, so there is supposed to be a link-local /64 on the loopback
> interface(s) providing many addresses to which a process could be
> separately bound, although a drawback of using the link-local prefix
> is having to deal with scope/zone IDs (although Linux doesn't comply
> with that requirement, it doesn't have a link-local address on the
> loopback interface by default).
>
> > and was the work picked up in any other draft.
>
> Not as far as I'm aware.
>
> What is your use case?
>
> Regards,
> Mark.
>
>
> >
> > Thanks
> >
> > Gyan
> >
> > Sent from my iPhone
>
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*Gyan Mishra*

*Network Solutions A**rchitect *



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