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Re: a draft about on-link and submit prefixes

sthaug@nethelp.no Tue, 14 March 2017 07:07 UTC

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Date: Tue, 14 Mar 2017 08:07:39 +0100
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To: lorenzo@google.com
Subject: Re: a draft about on-link and submit prefixes
From: sthaug@nethelp.no
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> If possible, I would suggest making this document even more general. It's
> mostly geared to how implementations treat PIOs, and refers to RFC 4861 and
> RFC 4862, but really I think the clarifications it makes have much broader
> impact. As I see it, the core issues here are:
> 
>    - IPv6 addresses don't specify any on-link information
>    - For most (but not all) unicast addresses, subnet prefixes are 64 bits
>    per RFC 4291.
>    - A given subnet prefix can be spread across multiple links, and a given
>    link can support multiple subnet prefixes.
> 
> This is not immediately obvious to people who are familiar with the IPv4
> subnet model, because it is quite different.

I agree that a generalization is a good idea. In particular, it would
be good to have (in one place) a definition of what an IPv6 subnet is,
especially if a subnet can be spread across multiple links (which is
*not* obvious to me from reading RFC 4861 and RFC 4862).

Steinar Haug, AS2116

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