Re: [Netconf] SSE and HTTP/2 in restcon-notif

[Kent Watsen <[e-mail]>]

> The text should be removed. How HTTP/2 sessions are started is defined
> in section 3 of RFC 7540.

Perfect.  This applies to all RESTCONF connections. Looking more at 
the first paragraph, the first sentence says:

   For a dynamic subscription, where an HTTP client session doesn't
   already exist, a new client session is initiated from the subscriber.

But this isn't quite right.  Dynamic subscriptions, at least for this
draft are always on top of a RESTCONF connection.  Put together, the
first paragraph should change as:

OLD:
   For a dynamic subscription, where an HTTP client session doesn't
   already exist, a new client session is initiated from the subscriber.
   If the subscriber is unsure if HTTP2 is supported by the publisher,
   HTTP1.1 will be used for initial messages, and these messages will
   include an HTTP version upgrade request as per [RFC7230],
   Section 6.7.  If a publisher response indicates that HTTP2 is
   supported, HTTP2 will be used between subscriber and publisher for
   future HTTP interactions as per [RFC7540].
NEW:
   Dynamic subscriptions are established using the RESTCONF protocol
   [RFC8040].  Section 2 of RFC 8040 describes the transport protocol
   for RESTCONF.

Also, while looking at Section 3.1, the second sentence says:

   A subscriber SHOULD establish the HTTP session over TLS [RFC5246]
   In order to secure the content in transit.

This sentence should be removed, RESTCONF requires TLS.  I imagine
this being a holdover from before, but another notif draft needs to
be written if wanting to support HTTP-based notifications without
requiring TLS, or even RESTCONF.

Similarly, the 3rd paragraph regards a scenario where TLS might not
be in use, which won't ever happen.  For this reason, the first half
of this paragraph should be removed.

Kent // contributor