Re: [netmod] 6991bis: address-with-prefix-length

Christian Hopps <chopps@chopps.org> Mon, 01 April 2019 21:50 UTC

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From: Christian Hopps <chopps@chopps.org>
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Date: Mon, 1 Apr 2019 17:50:05 -0400
In-Reply-To: <20190401.192951.1060904547331848297.mbj@tail-f.com>
Cc: Christian Hopps <chopps@chopps.org>, acee@cisco.com, netmod@ietf.org
To: Martin Bjorklund <mbj@tail-f.com>
References: <20190401161321.seiodlfsmjjvjcp5@anna.jacobs.jacobs-university.de> <F1537180-6BF3-40C7-BCFA-3AAE0290AE9D@cisco.com> <A0F7987F-AA67-4A63-8FEE-3B74B5B47CF1@cisco.com> <20190401.192951.1060904547331848297.mbj@tail-f.com>
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Subject: Re: [netmod] 6991bis: address-with-prefix-length
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> On Apr 1, 2019, at 1:29 PM, Martin Bjorklund <mbj@tail-f.com> wrote:
> 
> Hi,
> 
> The request was for a combined type that contains both an ip address
> *and* a prefix length in one value.  Hence the name
> "ip-address-and-prefix-length" :)
> 
> I know that this type is convenient, esp. if you use it for manual
> input, but I wonder if it really is good practice to squeeze two
> values into one.

This has value more than just convenience. In particular it captures and enforces the fact that the address has to be contained by the prefix (e.g., an interfaces address on the network it attaches to's prefix).

Thanks,
Chris.

> 
> 
> /martin
> 
> 
> "Acee Lindem (acee)" <acee@cisco.com> wrote:
>> Ok, now I'm confused. I see that the ietf-inet-type model already has the types ipv4-prefix and ipv6-prefix. How are these any different???
>> Thanks,
>> Acee
>> 
>> ´╗┐On 4/1/19, 12:31 PM, "Acee Lindem (acee)" <acee@cisco.com> wrote:
>> 
>>    I believe the "address-" could be omitted from the type identifiers. At least within the routing area, "ipv4-prefix" is unambiguous.
>>    Thanks,
>>    Acee
>> 
>>    On 4/1/19, 12:14 PM, "netmod on behalf of Juergen Schoenwaelder" <netmod-bounces@ietf.org on behalf of j.schoenwaelder@jacobs-university.de> wrote:
>> 
>>        This is the right time for this and I would call these
>>        ip-address-prefix, ipv4-address-prefix and ipv6-address
>>        prefix.
>> 
>>        /js
>> 
>>        On Mon, Apr 01, 2019 at 04:38:34PM +0200, Kristian Larsson wrote:
>>> Hello,
>>> 
>>> seeing that 6991 is up for a refresh I wonder if this would be the time to
>>> suggest the addition of a type for address-and-prefix-length, for example
>>> like 192.0.2.1/24?
>>> 
>>> I find that it's the most natural way express the address and prefix-length
>>> to configure on an interface or for some other use. We currently have an
>>> ip-prefix type which allows CIDR style prefixes but since all bits to the
>>> right of the mask is to be 0 it is only possible to use for describing the
>>> IP prefix / network address itself - not the address of a host in that
>>> network.
>>> 
>>> I actually wish the interface-ip modules would have used a combined leaf for
>>> these settings rather than the dual-leaf approach it currently has, but I
>>> suppose that ship has sailed :/
>>> 
>>> Regardless, can we add such a type? Is this the document and time to do it?
>>> :)
>>> 
>>> Kind regard,
>>>   Kristian.
>>> 
>>> _______________________________________________
>>> netmod mailing list
>>> netmod@ietf.org
>>> https://www.ietf.org/mailman/listinfo/netmod
>> 
>>        --
>>        Juergen Schoenwaelder           Jacobs University Bremen gGmbH
>>        Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
>>        Fax:   +49 421 200 3103         <https://www.jacobs-university.de/>
>> 
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>> 
>> 
>> 
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