Hi Yannis,

Please see inline.

Cheers,
Med

De : Softwires [mailto:softwires-boun...@ietf.org] De la part de Yannis 
Nikolopoulos
Envoyé : mercredi 9 août 2017 16:33
À : Softwires WG
Objet : [Softwires] Fwd: Re: I-D Action: 
draft-ietf-softwire-lightweight-4over6-deployment-01.txt


forwarding this to the list also, in case anyone cares to comment
regards,
Yannis

-------- Forwarded Message --------
Subject:

Re: [Softwires] I-D Action: 
draft-ietf-softwire-lightweight-4over6-deployment-01.txt

Date:

Sat, 8 Jul 2017 23:13:29 +0300

From:

Yannis Nikolopoulos <yan...@otenet.gr><mailto:yan...@otenet.gr>

To:

yiu_...@cable.comcast.com<mailto:yiu_...@cable.comcast.com>, 
xie...@ctbri.com.cn<mailto:xie...@ctbri.com.cn>, 
fib...@gmail.com<mailto:fib...@gmail.com>, tianxiang li 
<peter416...@gmail.com><mailto:peter416...@gmail.com>, Farrer, Ian (DTAG) 
<ian.far...@telekom.de><mailto:ian.far...@telekom.de>

CC:

Nikolopoulos Yannis <yan...@otenet.gr><mailto:yan...@otenet.gr>



Dear authors ,



as I said in the past, I believe that this is a very useful draft. We,

at OTE Greece are also deploying LW4o6 so if

you need to enrich the draft's test cases let me know.



Also, please find a few comments below:



"1. intro



 The logging requirements to meet regulatory requirements may be

      reduced as it is only necessary to log when a subscriber is

      provisioned or de-provisioned in the lwAFTR.  This relaxes the

      need for logging on a per-session, or per port block allocation."



[YN]: One still cannot comply with regulatory requirements because of

the A+P model (and because most servers on the internet do not log the

client's port number).So, how are the regulatory requirements reduced?



[Med] You are right. That text you quoted should explicitly mention that it 
assume that source port logging is used or that authorities in a given country 
are OK with reveal all the subscribers that are sharing a given address. This 
may be acceptable if a low address sharing ratio is used.



BTW, these considerations are not unique to A+P, but are the same for DS-Lite 
when port ranges are in used. In a DS-Lite context, logging the destination 
address + timestamping may be adequate, but there are trade-offs there: see 
https://tools.ietf.org/html/rfc6908#section-2.3



This following text should be updated:



OLD:


   This can bring a number of advantages when compared to DS-Lite:

   o  Per-subscriber configuration allows for the operator to provision
      each subscriber according to their specific service requirements.

  o  The logging requirements to meet regulatory requirements may be
      reduced as it is only necessary to log when a subscriber is
      provisioned or de-provisioned in the lwAFTR.  This relaxes the
      need for logging on a per-session, or per port block allocation.

   o  In some lw4o6 deployment topologies, the removal of per-session
      state means that it is possible to have very large parallelisation
      of lwAFTR elements.  This offers excellent scaling and resilience.

   o  This mechanism preserves the dynamic feature of IPv4/IPv6 address
      binding as in DS-Lite, so it has no coupling between IPv6 address
      and IPv4 address/port-set as any full stateless solution
      ([RFC6052<https://tools.ietf.org/html/rfc6052>] or 
[RFC7597<https://tools.ietf.org/html/rfc7597>]) requires.



NEW:


   This can bring a number of advantages when compared to DS-Lite:

   o  In some lw4o6 deployment topologies, the removal of per-session
      state means that it is possible to have very large parallelisation
      of lwAFTR elements.  This offers excellent scaling and resilience.



All other items are also valid for DS-Lite.





"3.1.  IP Addressing and Routing



   In Lightweight 4over6, there is no inter-dependency between the IPv4

   and IPv6 addressing schemes.  This allows for complete flexibilty in

   addressing architecture."



[YN]: although true, the above statement can be a bit misleading. I

believe that it should be mentioned that a proper addressing scheme for

IPv6 (lw4o6 esp.) should already be in place and ideally, IPv4 ranges

should be predefined (for routing efficienncy, e.g contiguous ranges)



[Med] I do think the text you quoted is accurate. There is no inter-dependency 
between IPv6 addressing and IPv4 one.



"3.1.1.  IPv4 Routing



   The IPv4 addresses/prefixes that are allocated to customer's lwB4s

   are advertised to the IPv4 Internet as being reachable via the

   lwAFTR(s).  If multiple lwAFTRs are all serving the same set of

   lwB4s, all will advertise the same IPv4 reachable routes."



YN: if multiple lwAFTRs, IPv4 prefixes could also be split, for routing

efficiency. That all depends on operator's and operator's upstream

topology and PoPs



[Med] Agree.





best regards,



Yannis





On 07/03/2017 06:58 PM, 
internet-dra...@ietf.org<mailto:internet-dra...@ietf.org> wrote:

> A New Internet-Draft is available from the on-line Internet-Drafts 
> directories.

> This draft is a work item of the Softwires of the IETF.

>

>          Title           : Deployment Considerations for Lightweight 4over6

>          Authors         : Qiong Sun

>                            Chongfeng Xie

>                            Yiu L. Lee

>                            Maoke Chen

>                            Tianxiang Li

>                            Ian Farrer

>      Filename        : 
> draft-ietf-softwire-lightweight-4over6-deployment-01.txt

>      Pages           : 23

>      Date            : 2017-07-03

>

> Abstract:

>     Lightweight 4over6 is a mechanism for providing IPv4 services to

>     clients connected to a single-stack IPv6 network.  The architecture

>     is similar to DS-Lite, but the network address translation function

>     is relocated from the tunnel concentrator to the tunnel client, hence

>     reducing the amount of state which must be maintained in the

>     concentrator to a per-customer level.  This document discusses the

>     applicability, describes various deployment models and provides

>     deployment considerations for Lightweight 4over6.

>

>

> The IETF datatracker status page for this draft is:

> https://datatracker.ietf.org/doc/draft-ietf-softwire-lightweight-4over6-deployment/

>

> There are also htmlized versions available at:

> https://tools.ietf.org/html/draft-ietf-softwire-lightweight-4over6-deployment-01

> https://datatracker.ietf.org/doc/html/draft-ietf-softwire-lightweight-4over6-deployment-01

>

> A diff from the previous version is available at:

> https://www.ietf.org/rfcdiff?url2=draft-ietf-softwire-lightweight-4over6-deployment-01

>

>

> Please note that it may take a couple of minutes from the time of submission

> until the htmlized version and diff are available at tools.ietf.org.

>

> Internet-Drafts are also available by anonymous FTP at:

> ftp://ftp.ietf.org/internet-drafts/

>

> _______________________________________________

> Softwires mailing list

> Softwires@ietf.org<mailto:Softwires@ietf.org>

> https://www.ietf.org/mailman/listinfo/softwires


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