[core] http observe unification

[Peter Bigot <[e-mail]>]

Cullen:

In the telecon yesterday, you objected to my proposal that the solution to
the observation problem be left to designers of specific systems.  It
sounded like you felt a reference document describing alternative approaches
that applications might take would not be adequate.  Could you elaborate a
little more here on what you believe CoAP must provide, and in what
timeframe?

I understood you to say that some IETF working group was nearly complete
with a proposed standard way to implement observation in HTTP.  Is that the
Httpbis group?  To which of their documents were you referring?
draft-loreto-http-bidirectional is somewhat relevant (wrt streaming
responses).

The clearly relevant one is draft-roach-sip-http-subscribe
s
, but that's based on SIP event notification.  Were we to take that
approach, it might be best to define a CoAP-like protocol "csip", rather
than integrate that functionality directly into CoAP.  On first glance, it
appears this would be at least as much work as defining CoAP has been.  It
would, though, give us a solution to observation, notification, and group
communication that is compatible with the HTTP family of protocols, so is
certainly worth considering.

Thanks.

Peter