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


-------- 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 <>
To:,,, tianxiang li <>, Farrer, Ian (DTAG) <>
CC:     Nikolopoulos Yannis <>

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?

"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)

"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

best regards,


On 07/03/2017 06:58 PM, 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        : 
        Pages           : 23
        Date            : 2017-07-03

    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.

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