Re: [Cbor] Supporting IPv6 Link-Local with scope (was Re: Éric Vyncke's Discuss on draft-ietf-cbor-network-addresses-09: (with DISCUSS and COMMENT))

Brian E Carpenter <brian.e.carpenter@gmail.com> Thu, 07 October 2021 20:18 UTC

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To: Michael Richardson <mcr+ietf@sandelman.ca>, "Rob Wilton (rwilton)" <rwilton@cisco.com>
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From: Brian E Carpenter <brian.e.carpenter@gmail.com>
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Date: Fri, 8 Oct 2021 09:18:38 +1300
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Subject: Re: [Cbor] =?utf-8?q?Supporting_IPv6_Link-Local_with_scope_=28was_Re?= =?utf-8?q?=3A_=C3=89ric_Vyncke=27s_Discuss_on_draft-ietf-cbor-network-add?= =?utf-8?q?resses-09=3A_=28with_DISCUSS_and_COMMENT=29=29?=
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On 08-Oct-21 07:31, Michael Richardson wrote:
> 
> Rob Wilton (rwilton) <rwilton@cisco.com> wrote:
>     > - How often are zones actually used?  Would it not just be simpler to
>     > always use a string interface identifier?
> 
> I don't think it would to always do that.

Definitely not. It depends on the application context, and as noted
earlier in the thread, translation between identifier and index is
system dependent, and both can change dynamically.

Also the index is fewer bytes, and in constrained nodes that
might matter.

   Brian

> My use case is that I have a (GRASP) daemon that discovers peers on
> particular interfaces, and it knows those interfaces by ifindex.
> It then tells another daemon (IKEv2) about those peers.
> If it did it by name, then that just forces both ends to do the
> name<->ifindex mapping for no gain.  I could live with that though.
> 
>     > - Is "false" for a prefix length a better choice than using either -1 or null?
> 
> We've gone for null.
> 
>     > 54([44, h'20010db81233'])
>     > 54([45, h'20010db8123f'])
> 
>     > ^- Should this be 44 rather than 45?  Because otherwise it looks like
>     > it would parse to a different prefix.
> 
> We've fixed it.
> I had some other wrong case in mind when I wrote 45 :-)
> 
> 
> --
> Michael Richardson <mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT consulting )
>            Sandelman Software Works Inc, Ottawa and Worldwide
> 
> 
> 
>