Re: [DNSOP] SVCB and HTTPSSVC records: draft-nygren-dnsop-svcb-httpssvc-00

Vladimír Čunát <> Thu, 26 September 2019 10:40 UTC

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Subject: Re: [DNSOP] SVCB and HTTPSSVC records: draft-nygren-dnsop-svcb-httpssvc-00
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On 9/26/19 12:30 PM, Jan Včelák wrote:
>> The current draft attempts to minimize complexity for implementers by offering a fully generic encoding for unknown key types.  For example, "alpn=h3" can also be expressed as "key1=h3", and "port=8003" can also be expressed as "key2=\031\067".  This encoding may not be convenient, but hopefully it will reduce the burden of supporting new parameter types.
> I agree we need generic encoding. There is a way to express unknown
> record types ( and the
> syntax used there is more compact than what you propose. It uses hex
> strings instead of escaped decimal values. However its clumsy to work
> with records in that syntax and you proposal is better in that sense.

I'm curious, Is there much motivation for a bit more compactness of the 
*presentation* format?  I consider its design primarily meant for humans.

> I think this may become the most complex record type we have in DNS so
> far. None of the existing registered record types contain a list of
> key-value pairs of arbitrary length. Given that there is also a
> registry for key types involved it will be fun to implement the
> encoder/decoder. But we will have to deal with it. I'm interested in
> what others in this working group think.

I think we should get "implementation experience" from multiple parties 
at least before publishing the RFC (though that's a point far ahead, I