Re: [DNSOP] [Ext] I-D Action: draft-ietf-dnsop-svcb-https-05.txt

Pieter Lexis <pieter.lexis@powerdns.com> Mon, 10 May 2021 15:23 UTC

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From: Pieter Lexis <pieter.lexis@powerdns.com>
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Date: Mon, 10 May 2021 17:23:03 +0200
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Subject: Re: [DNSOP] [Ext] I-D Action: draft-ietf-dnsop-svcb-https-05.txt
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Hi Joe,

On 5/10/21 1:42 AM, Joe Abley wrote:
> On May 9, 2021, at 19:27, Paul Hoffman <paul.hoffman@icann.org> wrote:
> 
>> If I'm wrong about this being as good as it can be, there must be an item delimiter that is better than a comma. I am not thinking creatively enough to figure out what might be better than a comma. I'd be happy to hear proposals for a better item delimiter. 
> 
> I am quite behind on this topic, but I presume there's a reason to put all these key-value pairs in a list in one RR?
> 
> If we compare the two fictional RRTypes EG1 and EG2 illustrated below:
> 
> example.com. EG1 key1=value1,key2=value2,...
> 
> example.com. EG2 key1 value1
> example.com. EG2 key2 value2
> 
> It seems to me that EG2 avoids the need for delimiters at all. There's a bit of overhead resulting from the need for a larger RRSet but it's not obvious that that's a proble>
> If the SvcParams field of the SVCB RR was a domain name rather than an explicit list this would all look a lot more DNS-like as far as parsing goes. This would also allow a single set of SvcParams key-value pairs to be included in different service bindings without having to be sent each time or to be bound to something provided a service provider (SVB in customer.org zone that refers to SvcParams.provider.com) giving the provider some ability to maintain some aspects of the service).

You then invite the following issues:

Clients need to match the tuple (ownername + prio + target) and get all
data from all matched rrsets, whereas now you get all that data in one
piece of rdata.

A client also can't figure out (if not doing DNSSEC valdiation
themselves) if you have received all the SVC data for a certain name.

Cheers,

Pieter