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Re: [core] ALPN "coap" for DTLS

Christian Amsüss <christian@amsuess.com> Fri, 23 February 2024 16:25 UTC

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Date: Fri, 23 Feb 2024 17:25:29 +0100
From: Christian Amsüss <christian@amsuess.com>
To: Michael Richardson <mcr+ietf@sandelman.ca>
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Subject: Re: [core] ALPN "coap" for DTLS
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On Fri, Feb 23, 2024 at 11:11:54AM -0500, Michael Richardson wrote:
> Will this apply to RFC9148, and therefore to draft-ietf-anima-constrained-voucher
> (which is no longer about vouchers, but about CoAP)?

I think so; any application using CoAP-over-DTLS will have the tools to
talk about the protocol it is using inside DTLS once this is registered
-- especially in the context of protocol discovery. 7252 did not mandate
sending an ALPN (how could it, predating them), and that doesn't changed
by having the value registered.

As constrained-voucher already specifies details about how DTLS is set
up, it may opt to prescribe using the ALPN, but I don't know whether
that'd be a good or bad thing or compatible or incompatible thing.

Does that work for you?

Christian

-- 
To use raw power is to make yourself infinitely vulnerable to greater powers.
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