Re: [Cbor] I-D Action: draft-ietf-cbor-network-addresses-04.txt

otroan@employees.org Tue, 27 April 2021 10:57 UTC

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Date: Tue, 27 Apr 2021 12:57:29 +0200
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Cc: Carsten Bormann <cabo@tzi.org>, cbor@ietf.org, 6man@ietf.org
To: Michael Richardson <mcr+ietf@sandelman.ca>
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Subject: Re: [Cbor] I-D Action: draft-ietf-cbor-network-addresses-04.txt
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Michael,

>>>> both and address and a prefix in one?
>>> 
>>> I don't understand your suggestion.
>>> X - address
>>> [n,X] - prefix
> 
>> Back in IPv4-land, we often said something like
> 
>> “Configure the interface to 192.168.3.5/24”
> 
> Ah, oh yes.
> Ole is this what you had in mind?

Yes. Although I think it equally applies to IPv6. An implementation should not and can not assume 64.

>> Which is a short-cut for
> 
>> “Configure the interface to address 192.168.3.5, prefix 192.168.3.0/24”
> 
>> Since address/prefix is structurally similar to a prefix (but uses a
>> full 32-bit address), it could be expressed by adding a third case
> 
>    <1> A - address
>    <2> [n,P] - prefix
>    <3> [A,n] - address/prefix
> 
> <3> is forced because case <2> demands that the trailing bits are zero, and
> are ideally omitted.  If we didn't insist on that, then we could do it all
> with one case.
> 
> I find the need for a third case a bit inelegant, but I can live with it.

It has it's pros and cons.
Configuring the on-link prefix and configuring the address are two separate things indeed.
It is a short-cut.

If you choose not to support it, it might be worth having a little blurb stating how configured an address and connected prefix would look like.


Best regards,
Ole