Re: [Dots] Adoption call for draft-reddy-dots-home-network-04

["Konda, Tirumaleswar Reddy" <[e-mail]>]

> -----Original Message-----
> From: [e-mail]
> <[e-mail]>
> Sent: Wednesday, April 24, 2019 6:42 PM
> To: Konda, Tirumaleswar Reddy
> <[e-mail]>; Valery Smyslov
> <[e-mail]>; [e-mail]
> Cc: [e-mail]; [e-mail]
> Subject: RE: [Dots] Adoption call for draft-reddy-dots-home-network-04
> 
> This email originated from outside of the organization. Do not click links or
> open attachments unless you recognize the sender and know the content is
> safe.
> 
> Re-,
> 
> Please see inline.
> 
> Cheers,
> Med
> > -----Message d'origine-----
> > De : Konda, Tirumaleswar Reddy
> > [mailto:[e-mail]]
> > Envoyé : mercredi 24 avril 2019 14:56
> > À : BOUCADAIR Mohamed TGI/OLN; Valery Smyslov; [e-mail] Cc :
> > [e-mail]; [e-mail] Objet : RE: [Dots] Adoption call
> > for draft-reddy-dots-home-network-04
> >
> > > -----Original Message-----
> > > From: [e-mail]
> > > <[e-mail]>
> > > Sent: Wednesday, April 24, 2019 4:48 PM
> > > To: Konda, Tirumaleswar Reddy
> > > <[e-mail]>; Valery Smyslov
> > > <[e-mail]>; [e-mail]
> > > Cc: [e-mail]; [e-mail]
> > > Subject: RE: [Dots] Adoption call for
> > > draft-reddy-dots-home-network-04
> > >
> > > This email originated from outside of the organization. Do not click
> > > links
> > or
> > > open attachments unless you recognize the sender and know the
> > > content is safe.
> > >
> > > Re-,
> > >
> > > Please see inline.
> > >
> > > Cheers,
> > > Med
> > >
> > > > -----Message d'origine-----
> > > > De : Konda, Tirumaleswar Reddy
> > > > [mailto:[e-mail]]
> > > > Envoyé : mercredi 24 avril 2019 13:01 À : BOUCADAIR Mohamed
> > > > TGI/OLN; Valery Smyslov; [e-mail] Cc :
> > > > [e-mail]; [e-mail] Objet : RE: [Dots] Adoption
> > > > call for draft-reddy-dots-home-network-04
> > > >
> > > > > -----Original Message-----
> > > > > From: [e-mail]
> > > > > <[e-mail]>
> > > > > Sent: Wednesday, April 24, 2019 12:18 PM
> > > > > To: Konda, Tirumaleswar Reddy
> > > > > <[e-mail]>; Valery Smyslov
> > > > > <[e-mail]>; [e-mail]
> > > > > Cc: [e-mail]; [e-mail]
> > > > > Subject: RE: [Dots] Adoption call for
> > > > > draft-reddy-dots-home-network-04
> > > > >
> > > > >
> > > > >
> > > > > Re-,
> > > > >
> > > > > Please see inline.
> > > > >
> > > > > Cheers,
> > > > > Med
> > > > >
> > > > > > -----Message d'origine-----
> > > > > > De : Konda, Tirumaleswar Reddy
> > > > > > [mailto:[e-mail]]
> > > > > > Envoyé : mercredi 24 avril 2019 08:13 À : BOUCADAIR Mohamed
> > > > > > TGI/OLN; Valery Smyslov; [e-mail] Cc :
> > > > > > [e-mail]; [e-mail] Objet : RE: [Dots]
> > > > > > Adoption call for draft-reddy-dots-home-network-04
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Dots <[e-mail]> On Behalf Of
> > > > > > > [e-mail]
> > > > > > > Sent: Wednesday, April 24, 2019 11:26 AM
> > > > > > > To: Valery Smyslov <[e-mail]>; [e-mail]
> > > > > > > Cc: [e-mail]; [e-mail]
> > > > > > > Subject: Re: [Dots] Adoption call for
> > > > > > > draft-reddy-dots-home-network-04
> > > > > > >
> > > > > > > This email originated from outside of the organization. Do
> > > > > > > not click links
> > > > > > or
> > > > > > > open attachments unless you recognize the sender and know
> > > > > > > the content is safe.
> > > > > > >
> > > > > > > Re-,
> > > > > > >
> > > > > > > Please see inline.
> > > > > > >
> > > > > > > Cheers,
> > > > > > > Med
> > > > > > >
> > > > > > > > -----Message d'origine----- De : Dots
> > > > > > > > [mailto:[e-mail]] De la part de Valery
> > > > > > > > Smyslov Envoyé : mercredi 24 avril 2019 07:02 À :
> > > > > > > > [e-mail]
> > Cc :
> > > > > > > > [e-mail]; [e-mail] Objet : Re: [Dots]
> > > > > > > > Adoption call for draft-reddy-dots-home-network-04
> > > > > > > >
> > > > > > > > Hi,
> > > > > > > >
> > > > > > > > we received a lot of replies supporting adoption of the
> document.
> > > > > > > > So, the document is adopted. Authors, please re-submit it
> > > > > > > > as WG
> > > > draft.
> > > > > > > >
> > > > > > > > A couple of comments.
> > > > > > > > 1. The draft uses few times a keyword "MAY NOT". This
> > > > > > > > combination is
> > > > > not
> > > > > > > >      among the list of RFC requirement keywords (it is not
> > > > > > > > listed
> > > > neither
> > > > > > > >      in RFC2119, nor in RFC8174). If the intent was to use
> > > > > > > > RFC
> > > > > > requirement
> > > > > > > >      language, then I'd suggest replacing it with one of
> > > > > > > > MUST NOT, SHALL NOT,
> > > > > > > >      SHOULD NOT. Otherwise please make it lowcase.
> > > > > > > >
> > > > > > >
> > > > > > > [Med] Good catch. Fixed.
> > > > > > >
> > > > > > > > 2. When describing transport, the draft allows both TLS and DTLS.
> > > > What
> > > > > > > >      makes me confusing is that the draft describes it
> > > > > > > > several times as "TCP/TLS or DTLS".
> > > > > > > >      Why TCP is ever mentioned here? We all know that TLS
> > > > > > > > usually runs
> > > > > > over
> > > > > > > >      TCP (however we now have QUICK) and DTLS runs over UDP.
> > > > > > > >      The way it is presented in the draft makes me think
> > > > > > > > that
> > > > probably
> > > > > > > >      plain TCP is also allowed as a transport, but is
> > > > > > > > seems to
> > > > contradict
> > > > > > > >      everything I read about DOTS. Am I missing something here?
> > > > > > > >
> > > > > > >
> > > > > > > [Med] Plain TCP is not allowed. The intent was to be
> > > > > > > explicit that there is
> > > > > > a
> > > > > > > reversal in both TCP and TLS layers, but as you rightfully
> > > > > > > raised this may
> > > > > > be
> > > > > > > confusing since, for the DOTS case, it is trivial that the
> > > > > > > reversal of TLS
> > > > > > roles
> > > > > > > implies the reversal of TCP ones.
> > > > > >
> > > > > > RESTCONF call home only reverses the TCP role but not the TLS
> > > > > > role. In DOTS case, the server has to initiate DTLS handshake
> > > > > > for UDP. To keep the roles same for TCP,  TLS handshake is
> > > > > > also initiated
> > by
> > > the server.
> > > > >
> > > > > [Med] You missed "for the DOTS case" in my previous reply :-)
> > > > >
> > > > > We do have the following in the draft:
> > > > >
> > > > >                    DOTS                                DOTS
> > > > >                   Server                              Client
> > > > >                     |                                    |
> > > > >                     |         1. (D)TLS connection       |
> > > > >                     |----------------------------------->|
> > > > >                     |         2. Mitigation request      |
> > > > >                     |<-----------------------------------|
> > > > >                     |                                    |
> > > > >
> > > > > That can be trivially expanded as follows for the TLS case:
> > > > >
> > > > >                    DOTS                                DOTS
> > > > >                   Server                              Client
> > > > >                     |                                    |
> > > > >                     |         1.1. TCP                   |
> > > > >                     |----------------------------------->|
> > > > >                     |         1.2. TLS                   |
> > > > >                     |----------------------------------->|
> > > > >                     |         2. Mitigation request      |
> > > > >                     |<-----------------------------------|
> > > > >                     |                                    |
> > > >
> > > > Okay.
> > > >
> > > > >
> > > > >
> > > > > As mentioned earlier, the use of TCP/TLS is OK but it may be
> > > > > confusing as initially raised by Valery.
> > > >
> > > > The updated text is not accurate if TCP is not covered, role
> > > > reversal at TLS does not mean role reversal at TCP.
> > >
> > > [Med] The updated text is still fine (ref to Figure 1). We don't
> > > have any ambiguity in the procedure part with regards to TCP. We
> > > explicitly say the
> > > following:
> > >
> > >        If TCP is used, the DOTS server begins by initiating a TCP
> > >        connection to the DOTS client.  The DOTS client MUST support
> > >        accepting TCP connections on the IANA-assigned port number
> > >        defined in Section 4.1, but MAY be configured to listen to a
> > >        different port number.  Using this TCP connection, the DOTS
> > >        server initiates a TLS connection to the DOTS client.
> > >
> > > > Similar to (D)TLS, I prefer explicit text to say role reversal at TCP.
> > >
> > > [Med] We already have such text (see the above excerpt).
> >
> > [TR] Yes, but the updated sentences are incomplete/incorrect at
> > various places. I have listed one of the inconsistencies below
> >
> >    The one and only role reversal that
> >    occurs are at the TLS or DTLS layers; that is, the DOTS server acts
> >    as a DTLS client and the DOTS client acts as a DTLS server or the
> >    DOTS server acts as a TLS client and the DOTS client acts as a TLS
> >    server.  The DOTS server initiates TLS handshake or DTLS handshake to
> >    the DOTS client.
> >
> > The above update means no role reversal at the TCP layer !
> 
> [Med] This text assumes that the TCP is implicitly covered by "TLS layer"
> (refer again to Figure 1). There is no ambiguity that the reversal at the TLS
> layer for the DOTS case implies a reversal of the TCP roles, because
> otherwise the connection cannot be established at the first place (due to the
> presence of NATs/FWs) !

If NAT is not present, connection can be established. FW can be configured to permit TCP connections from external peer (e.g. port forwarding).

> 
> We can removed "one and only" if this really hurts, though.

I propose the following additional change:

    The role reversal that
    occurs are at the TLS or DTLS layers; that is, the DOTS server acts
    as a DTLS client and the DOTS client acts as a DTLS server or the
   DOTS server acts as a TLS client initiating the underlying TCP connection and the DOTS client acts as a TLS
   server.  The DOTS server initiates TLS handshake or DTLS handshake to
   the DOTS client.

-Tiru