Subject: [core] pubsub-05: why UNSUBSCRIBE?

From: Christian Amsüss <[email-masked]>
Date: Wed, 20 Jul 2016 23:53:45 +0200

Hello Michael,

late as always I'm just reading the pubsub draft. Apart from me not
being convinced that this the proposed way is the right way to implement
the pubsub pattern on CoAP (maybe it is, I'd love to chat about the
rationale in another thread/conversation), I'm wondering about
UNSUBSCRIBE:

Why is this a dedicated operation? I do not find anything in there that
is not obvious behavior from there being an active observation that can
(just as laid out in RFC 7641) can be cancelled.  I do see that coming
from a pubsub mindset this is an operation, but on the CoAP side I would
not see it as an operation (with all its attached Method and URI and
what not details), and would rather informally state that an
"UNSUBSCRIBE" mechanism is expressed by cancellation of the observation
obtained in the SUBSCRIBE mechanism.

See you tomorrow
Christian

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