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

[<[e-mail]>]

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). 

 The
> security considerations section says " DOTS agents MUST authenticate each
> other using (D)TLS before a DOTS
> signal channel session is considered valid.", so clear text DOTS traffic is
> ruled out.

[Med] Fully agree.