Re: [Softwires] Unified Softwire CPE: draft-bfmk-softwire-unified-cpe

[<[e-mail]>]

Hi Woj,

Many thanks for the comments. 

Please see inline. 

Cheers,
Med 

>-----Message d'origine-----
>De : Wojciech Dec (wdec) [mailto:[e-mail]] 
>Envoyé : vendredi 30 novembre 2012 11:42
>À : BOUCADAIR Mohamed OLNC/OLN; 
>[e-mail]; 
>[e-mail]; 
>[e-mail]; 
>draft-cui-softwire-b4-translated-ds-lite; Reinaldo Penno 
>(repenno); [e-mail]
>Objet : Re: Unified Softwire CPE: draft-bfmk-softwire-unified-cpe
>
>Hi,
>
>While thanking the authors for their attempt, I need to 
>provide some high
>level feedback first on key issues:

>The rationale section 1.1 states "co-existance" as the goal - 
>this appears
>to imply some entirely different solutions for which co-existance is
>needed", and here are two points:
>A) I can agree that DS.-lite is an entirely different solution, but I
>firmly believe that it is entirely outside the agreed scope which was a
>"unified solution CPE spec" in the context of MAP and Lw4o6. 
>Thus, I would
>recommend that ds.-lite be dropped from this draft as it bears no
>influence on "unifying" MAP and Lw4o6, nor does it bear anything on the
>already "defined and shipped" ds.-lite solution. Work on such themes of
>"multiple solutions coexisting" is what the v6ops CPE draft is covering
>and I would place ds.-lite coexistence there.

Med: We included DS-Lite in the scope because of the following:

* Several WG participants are concerned with optimizing the code and re-using existing modules. 
* Some DS-Lite components are shared with A+P solution: e.g., tunnel endpoint
* A+P may be seen as an exit strategy of the CGN: optimisation migration path and required changes in the CPEs need to be taken into account. 

>
>B) I disagree that "co-existance" between Lw4o6 and MAP is a goal;

Med: MAP1:1 and lw4o6 are presented in the draft as soltuions for the binding mode.  

 a
>unified functional CPE spec for NAT44-less core relays 
>accessed via IPv6
>is. As such, describing "modes" as in "solution modes" is not 
>conductive
>to that and a solution term neutral functional breakdown is 
>essential and
>IMO possible (further explained below). This will only make the spec
>better and simpler for implementers.

Med: This is what we tried to do in  http://tools.ietf.org/html/draft-bfmk-softwire-unified-cpe-00#section-4.3. 

>
>In Section 3 the draft coin a new term/class of solution 
>called "Binding
>approach".

Med: FYI, this is not a new term: please refer to http://tools.ietf.org/html/rfc6346#section-4.4.


>This effectively refers to configuration state which *all* 
>solutions need,
>and is not helpful in providing anything but more verbiage. 
>Removing this
>classification from all of the text is recommended.

Med: IMHO this is the core of the discussion between MAP and Lw4o6 teams. Having a neutral terminology and a full understand of what this is about is IMHO important to converge. 

>
>Further in section 3 the draft lists different functional 
>elements, and it
>is here that major changes are needed.

Med: Section 3 is to be seen as a reminder for the solution flavors we have on the table. This section can be moved to an appendix. I would expect we focus our discussion on Section 4.

 For a unified solution 
>a functional
>breakdown in a solution neutral text is essential. 

Med: We really tried to adopt a neutral terminology in Section 4. Suggestions are welcome on how to enhance that section.

IMO A unified CE has
>the following basic functionalities, which I propose to be added to the
>text in place of the existing one:

Med: Could you please point me which text you are referring to? Thanks. 

>- IPv4 NAT whose address and port restrictions are configurable
>- an IPv6 transport whose source and destination transport address are
>deterministically derived/configurable
>
>- an IPv4 routing capability (also configurable)

Med: What does that mean?

>
>In example terms, consider a CPE configured with IPv4 address, 
>restricted
>Port range X and IPv6 source address Y and transport address Z.
>There is no difference in these parameters between Lw4o6 and 
>MAP, and it
>shows the essence of what we need to get at.

Med: Isn't that what is captured in "Table 3: Supported Features" ?

   +--------------+----------------+-----------------+-----------------+
   |   Functional |  IPv4-in-IPv6  | Port-restricted | Port-restricted |
   |      Element |     tunnel     |       IPv4      |      NAT44      |
   |              |    endpoint    |                 |                 |
   +--------------+----------------+-----------------+-----------------+
   |           B4 |       Yes      |       N/A       |        No       |
   +--------------+----------------+-----------------+-----------------+
   |         lwB4 |       Yes      |       Yes       |     Optional    |
   +--------------+----------------+-----------------+-----------------+
   |     MAP-E CE |       Yes      |       Yes       |     Optional    |
   +--------------+----------------+-----------------+-----------------+


>
>
>One can comment further on the details of the draft, but 
>getting the basic
>functional breakdown is essential (example above) before we 
>get into that.
> The only thing different between the solutions are not the basic
>functionalities but rather how this functionality is configured.

Med: I guess you are talking about MAP1:1 and LW4over6.

>
>Regards,
>Woj..
>
>
>
>On 29/11/2012 11:16, "[e-mail]"
><[e-mail]> wrote:
>
>>Dear all,
>>
>>As agreed in Atlanta, we prepared an I-D describing a 
>proposed approach
>>for the unified CPE.
>>
>>We hope this version is a good starting point to have fruitful
>>discussion. 
>>
>>Your comments, suggestions and contributions are more than welcome.
>>
>>Cheers,
>>Med
>>
>>
>>-----Message d'origine-----
>>De : [e-mail] 
>[mailto:[e-mail]]
>>De la part de [e-mail]
>>Envoyé : jeudi 29 novembre 2012 10:57
>>À : [e-mail]
>>Objet : I-D Action: draft-bfmk-softwire-unified-cpe-00.txt
>>
>>
>>A New Internet-Draft is available from the on-line Internet-Drafts
>>directories.
>>
>>
>>	Title           : Unified Softwire CPE
>>	Author(s)       : Mohamed Boucadair
>>                          Ian Farrer
>>                          Suresh Krishnan
>>	Filename        : draft-bfmk-softwire-unified-cpe-00.txt
>>	Pages           : 12
>>	Date            : 2012-11-29
>>
>>Abstract:
>>   Transporting IPv4 packets over IPv6 is a common solution to the
>>   problem of IPv4 service continuity over IPv6-only provider 
>networks.
>>   A number of differing functional approaches have been developed for
>>   this, each having their own specific characteristics.  As these
>>   approaches share a similar functional architecture and use the same
>>   data plane mechanisms, this memo describes a specification 
>whereby a
>>   single CPE can interwork with all of the standardized and proposed
>>   approaches to providing encapsulated IPv4 in IPv6 services.
>>
>>
>>The IETF datatracker status page for this draft is:
>>https://datatracker.ietf.org/doc/draft-bfmk-softwire-unified-cpe
>>
>>There's also a htmlized version available at:
>>http://tools.ietf.org/html/draft-bfmk-softwire-unified-cpe-00
>>
>>
>>Internet-Drafts are also available by anonymous FTP at:
>>ftp://ftp.ietf.org/internet-drafts/
>>
>>_______________________________________________
>>I-D-Announce mailing list
>>[e-mail]
>>https://www.ietf.org/mailman/listinfo/i-d-announce
>>Internet-Draft directories: http://www.ietf.org/shadow.html
>>or ftp://ftp.ietf.org/ietf/1shadow-sites.txt
>
>