Re: Metadata over IPv6

[Bob Hinden <[e-mail]>]

> On Dec 17, 2019, at 12:32 PM, Mark Smith <[e-mail]> wrote:
> 

……….

> Ah, Ok.  So does everything on the link use the same address format?  We
> are dealing with pre-existing deployments where we can't change that.  I
> do like the fact that AERO basically has the format we're looking for,
> fe80::ffff:169.254.169.254, which make it obvious this is the metadata
> service IP.
> 
> I think it would be better to reserve a proper IPv6 anycast address for this from within the upper 128 IID values, unless there is a specific reason to tie it to the IPv4 address version of the service.
> 
> https://www.iana.org/assignments/ipv6-anycast-addresses/ipv6-anycast-addresses.xhtml
> 
> Coupling things to IPv4 ways, even just symbolically, increases momentum against giving up IPv4.
> 
> It's better to do things the native "IPv6 way”.

I agree, if this is intended for an IPv6-only network, then it would be much better to avoid using an encoded IPv4 address.

Getting an IPv6 anycast assigned seems like a reasonable approach to me.

Bob


> Amazon shouldn't be hijacking a IPv4 Link-Local addresses for special purposes like that. If somebody else does the same thing, then there are two unofficial meanings for the same address. The argument that Amazon has already reserved that address doesn't fly when they actually officially haven't. Amazon should have requested a properly reserved anycast address from IANA.
> 
> People used 1/8 for that sort of thing. That caused problems when APNIC started using it for its proper purpose - public Internet addressing.
> 
> Traffic in Network 1.0.0.0/8
> 
> http://www.potaroo.net/studies/1slash8/1slash8.html
> 
> Regards,
> Mark.
> 
> 
> 
> -Brian
> 
> 
> >> Just that
> >> "Relay, Server and Proxy AERO addresses are allocated from the range
> >> fe80::/96, and MUST be managed for uniqueness."
> >
> > You are referring to something different here that does not apply to the use case
> > of embedding an IPv4 address in an IPv6 address - so, this part of the AERO spec
> > is out of scope for what we are discussing here.
> >
> > Thanks - Fred
> >
> >> since we do control
> >> the MAC we could do this I suppose as we want this link-local on the
> >> proxy, but what we're doing isn't really akin to AERO (IMO).
> >>
> >> Thanks,
> >>
> >> -Brian
> 
> --------------------------------------------------------------------
> IETF IPv6 working group mailing list
> [e-mail]
> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
> --------------------------------------------------------------------
> --------------------------------------------------------------------
> IETF IPv6 working group mailing list
> [e-mail]
> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
> --------------------------------------------------------------------