Re: [Dots] Alissa Cooper's Discuss on draft-ietf-dots-signal-channel-31: (with DISCUSS and COMMENT)

[<[e-mail]>]

Hi Alissa, 

Please see inline.

Cheers,
Med

> -----Message d'origine-----
> De : Alissa Cooper via Datatracker [mailto:[e-mail]]
> Envoyé : jeudi 2 mai 2019 03:56
> À : The IESG
> Cc : [e-mail]; Liang Xia; dots-
> [e-mail]; [e-mail]; [e-mail]
> Objet : Alissa Cooper's Discuss on draft-ietf-dots-signal-channel-31: (with
> DISCUSS and COMMENT)
> 
> Alissa Cooper has entered the following ballot position for
> draft-ietf-dots-signal-channel-31: Discuss
> 
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> 
> Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
> for more information about IESG DISCUSS and COMMENT positions.
> 
> 
> The document, along with other ballot positions, can be found here:
> https://datatracker.ietf.org/doc/draft-ietf-dots-signal-channel/
> 
> 
> 
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
> 
> = Section 3 =
> 
> "By default, a DOTS signal channel MUST run over port number TBD as
>    defined in Section 9.1, for both UDP and TCP, unless the DOTS server
>    has a mutual agreement with its DOTS clients to use a different port
>    number.  DOTS clients MAY alternatively support means to dynamically
>    discover the ports used by their DOTS servers (e.g.,
>    [I-D.boucadair-dots-server-discovery])."
> 
> MUST implies an absolute requirement, so "MUST ... unless" is a problematic
> construction.

[Med] It seems that you missed "By default, ". 


 Furthermore, it doesn't make sense together with "MAY
> alternatively," which indicates that port number discovery is an alternative
> to
> the fixed to-be-assigned port.
> 
> I didn't have time to get very far into draft-boucadair-dots-server-
> discovery,

[Med] I updated that reference to I-D.ietf-dots-server-discovery. 

> but it appears that it does not mandate support for any single discovery
> mechanism for clients and servers to support. If so, that "alternatively"
> seems
> like more of a problem, since it allows for there to be no interoperable
> mechanism for clients to discover server ports. I think maybe what was
> intended
> here was:
> 
> s/MUST/SHOULD/
> s/MAY alternatively/MAY additionally/

[Med] I implemented the second change. 

> 
> = Section 4.4.1 =
> 
> (1)
> "In deployments where server-domain DOTS gateways are enabled,
>    identity information about the origin source client domain SHOULD be
>    propagated to the DOTS server.  That information is meant to assist
>    the DOTS server to enforce some policies such as grouping DOTS
>    clients that belong to the same DOTS domain, limiting the number of
>    DOTS requests, and identifying the mitigation scope.  These policies
>    can be enforced per-client, per-client domain, or both.  Also, the
>    identity information may be used for auditing and debugging purposes."
> 
> Does "identity information" just refer to cdid, or something else?

[Med] It refers to the information conveyed in cdid. 

> 
> (2) The constructions "MUST ... (absent explicit policy/configuration
> otherwise)" are problematic. I'm assuming these are meant to be SHOULDs.
> 

[Med] I checked this wording with Ben.  

> = Section 13.1 =
> 
> I don't understand why RFC 7951 is a normative reference but
> draft-ietf-core-yang-cbor is an informative reference.

[Med] We used to have both as informative references, but unless I'm mistaken 7951 was moved to normative so that at least one method is supported.

> 
> 
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
> 
> = Section 4.4.1 =
> 
> "The 'cuid' is intended to be stable when communicating with a
>       given DOTS server, i.e., the 'cuid' used by a DOTS client SHOULD
>       NOT change over time. "
> 
> Why is this the recommended behavior?
> 

[Med] because all resources/state of a DOTS client are bound to this identifier.