I think this is about multiple values within an SvcParamValue. The referenced figure, as well as text in section 8, make it clear that values in the mandatory SvcParam cannot be repeated. There’s no such text for other parameters, like ipv4hint and ipv6hint, which are described in section 7.3 as "an unordered collection”, with no mention of sorting or duplicates.
I’ve also been thinking about this, although mostly in the context of DELEG. Brian > On Oct 23, 2025, at 6:54 AM, Ben Schwartz <[email protected]> > wrote: > I'm not sure I understand the question. > > Duplicate SvcParamKeys are prohibited, even if the value is the same: > > Forbidden: examplekey=examplevalue examplekey=examplevalue > > Repeated entries in a list-valued SvcParamValue are permissible, if allowed > by the SvcParamKey definition: > > Forbidden: mandatory=ech,ech > > Ostensibly permitted but very silly and please don't: alpn=h2,h3,h2 > ipv6hint=2006:db8::1,2006:db8::1 > > Possibly useful: example-flags=1,0,0,1 > > --Ben > > From: Petr Špaček <[email protected] <mailto:[email protected]>> > Sent: Thursday, October 23, 2025 7:45 AM > To: dnsop <[email protected] <mailto:[email protected]>>; Ben Schwartz > <[email protected] <mailto:[email protected]>> > Subject: RFC 9460 SvcParamValue question - duplicate values > > > > Hi. > > RFC 9460 section D.3. Failure Cases figure Figure 16: Multiple Instances > of the Same SvcParamKey in the Mandatory List got me thinking - are > multiple identical values in SvcParamValue generally allowed or disallowed? > > I would think they are allowed because there's no requirement to order > them and the check might be expensive. > > Am I correct? > > -- > Petr Špaček > Internet Systems Consortium > _______________________________________________ > DNSOP mailing list -- [email protected] > To unsubscribe send an email to [email protected]
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