Re: [core] [Anima] constrained resources at root for debugging connectivity

Olaf Bergmann <bergmann@tzi.org> Thu, 22 July 2021 09:53 UTC

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From: Olaf Bergmann <bergmann@tzi.org>
To: Michael Richardson <mcr+ietf@sandelman.ca>
Cc: Esko Dijk <esko.dijk@iotconsultancy.nl>, "anima@ietf.org" <anima@ietf.org>, "core@ietf.org" <core@ietf.org>
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Date: Thu, 22 Jul 2021 11:53:07 +0200
In-Reply-To: <25674.1626896178@localhost> (Michael Richardson's message of "Wed, 21 Jul 2021 15:36:18 -0400")
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Subject: Re: [core] [Anima] constrained resources at root for debugging connectivity
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Michael,

On 2021-07-21, Michael Richardson <mcr+ietf@sandelman.ca> wrote:

> Esko Dijk <esko.dijk@iotconsultancy.nl> wrote:
>     > There is already a "CoAP ping" described in RFC 7252 that can be
>     > used. It does not access any resource, just the CoAP server endpoint at
>     > CoAP message layer. As a side effect of this ping your DTLS stack will
>     > set up the connection which is handy.
>
> I recalled that later in the day that CoAP "ping" is not connected to CoAP
> "echo" :-)
> I think that there is also potentially a need for a way to debug possible MTU
> issues.
> Is there a way to use Olaf's "coap-client" to do the ping?

-K does that, see man coap-client (https://libcoap.net/doc/reference/develop/man_coap-client.html):

      -K interval
           Send a ping after interval seconds of inactivity. If
           not specified (or 0), keep-alive is disabled (default).

It would be not difficult to create a dedicated coap-ping, though.

> I don't see an option, and it also doesn't seem to be commonly built
> with DTLS.

It is automatically built with DTLS if you have either GnuTLS, OpenSSL,
Mbed TLS with headers installed (--enable-dtls is default).

Grüße
Olaf