RE: Loopback interface terminology issue

["Templin, Fred L" <[e-mail]>]

Hi Michael,

> -----Original Message-----
> From: ipv6 [mailto:[e-mail]] On Behalf Of Michael Richardson
> Sent: Wednesday, October 18, 2017 9:44 AM
> To: [e-mail]
> Subject: Re: Loopback interface terminology issue
> 
> 
> Templin, Fred L <[e-mail]> wrote:
>     >> On 17/10/2017 12:15, Templin, Fred L wrote: > Brian,
>     >> >
>     >> > Here is what it says in 'draft-templin-v6ops-pdhost':
>     >> >
>     >> > "This document also considers the case when 'R' does not have any >
>     >> downstream interfaces, and can use 'P' solely for its own internal >
>     >> addressing purposes.  In that case, 'R' assigns 'P' to a virtual >
>     >> interface (e.g., a loopback) that fills the role of a downstream >
>     >> interface.
>     >> >
>     >> > 'R' can then function under the weak end system (aka "weak host") >
>     >> model [RFC1122][RFC8028] by assigning addresses taken from 'P' to a >
>     >> virtual interface as shown in Figure 2:"
>     >> >
>     >> > Internal virtual interfaces were also discussed in RFC5558.
>     >>
>     >> Well yes; indeed this topic is touched on in many RFCs but nowhere is
>     >> it defined as part of the basic architecture, which is my main
>     >> point. Using a concept that has no principal definition is generally a
>     >> source of confusion.
> 
>     > I agree that it has been touched on in many earlier works, also
>     > including 'draft-templin-aerolink' and many of my published RFCs.
> 
>     > But, I must say that it now also appears in RFC7934 (a BCP).
> 
> I scanned RFC7934, and it too would have benefitted from some
> canonical text to explain non-loopback addresses on (virtual) loopback
> interfaces.
> 
> The two questions that Brian has are, I think:
> 
> 1) how can we best explain this in a way that takes what has been a
>    (multi-decade old) operational BCP, and makes it clear that it's a
>    standard mechanism?
> 
> 2) where would we put this text, such that if we were to write a short
>    document, what would we "Updates"
> 
>    I'm thinking that an update to RFC8028 would make sense, and that
>    the scope/title of an 8028bis might change slightly as a result such text,
>    because maybe all hosts actually live in a multi-prefix networks...

Non-loopback addresses that would be assigned to a loopback interface would
have to come from a delegated IPv6 prefix. Please see 'draft-templin-v6ops-pdhost'
for procedures of how to assign addresses from a delegated prefix to a loopback
or other virtual interface:

https://datatracker.ietf.org/doc/draft-templin-v6ops-pdhost/

This document stems from my earlier works including RFC5558, RFC6179
and 'draft-templin-aerolink' which talk about assigning delegated prefixes
to internal virtual interfaces such as loopbacks. But, the 'pdhost' draft is
still open for edits - should it be made standards-track?

Thanks - Fred

> --
> Michael Richardson <[e-mail]>, Sandelman Software Works
>  -= IPv6 IoT consulting =-
> 
>