understanding IPv6

Pascal Thubert (pthubert) pthubert at cisco.com
Sun Jun 7 19:05:53 UTC 2020

Hello Joel:

The draft is supposed to be factual not divagations; if I went too far somewhere I need to fix the draft. As you said it is early personal submission.

Multi links subnets are not a figment of my mind. We have millions of routers deployed that way, using RPL as the subnet routing protocol. Admittedly this is IoT but this is true nevertheless.

Keep safe,


> Le 7 juin 2020 à 21:00, Joel Halpern <jmh at joelhalpern.com> a écrit :
> Just to clarify context, at this stage this is just Pascal's interesting idea for how to make ND work better on wireless.  No IETF working group has adopted this.  Various people seem to be interested, but it will be some time before we know if his approach gets traction.
> The biggest difference between this and earlier changes along this line is that the wireless broadcast problem provides motivation for the change, where earlier efforts were more ~wouldn't it just be simpler if...~
> Yours,
> Joel Halpern
>> On 6/7/2020 2:28 PM, Etienne-Victor Depasquale wrote:
>> What I'm amazed at is the concept of multi-link subnet and the change in IP model being proposed.
>> See, for example, section 4 of https://tools.ietf.org/html/draft-thubert-6man-ipv6-over-wireless-05
>> Has anyone felt the same about the change being proposed? This swept away 25 years of thinking about IP subnets and IP links for me.
>> Etienne
>> On Sun, Jun 7, 2020 at 6:03 PM Brandon Martin <lists.nanog at monmotha.net <mailto:lists.nanog at monmotha.net>> wrote:
>>    On 6/7/20 6:01 AM, Denys Fedoryshchenko wrote:
>>     > There are very interesting and unobvious moments on IPv4 vs IPv6,
>>    for
>>     > example related to battery lifetime in embedded electronics. In
>>    ipv4,
>>     > many devices are forced to send "keepalives" so that the NAT
>>    entry does
>>     > not disappear, with IPv6 it is not required and bidirectional
>>     > communications possible at any time. And in fact, it has a huge
>>    impact
>>     > on the cost and battery life of IoT devices.
>>     > When I developed some IoT devices for clients, it turned out that if
>>     > "IPv6-only" is possible, this significantly reduces the cost of the
>>     > solution and simplify setup.
>>    This is difficult to understate.  "People" are continually amazed
>>    when I
>>    show them that I can leave TCP sessions up for days at a time (with
>>    properly configured endpoints) with absolutely zero keepalive traffic
>>    being exchanged.
>>    As amusingly useful as this may be, it pales in comparison to the
>>    ability to do the same on deeply embedded devices running off small
>>    primary cell batteries.  I've got an industrial sensor network product
>>    where the device poll interval is upwards of 10 minutes, and even then
>>    it only turns on its receiver.  The transmitter only gets lit up about
>>    once a day for a "yes I'm still here" notification unless it has
>>    something else to say.
>>    In the end, we made it work across IPv4 by inserting an application
>>    level gateway.  We just couldn't get reliable, transparent IPv6
>>    full-prefix connectivity from any of the cellular telematics providers
>>    at the time.  I don't know if this has changed.  For our application,
>>    this was fine, but for mixed vendor "IoT" devices, it would probably
>>    not
>>    work out well.
>>    --     Brandon Martin
>> -- 
>> Ing. Etienne-Victor Depasquale
>> Assistant Lecturer
>> Department of Communications & Computer Engineering
>> Faculty of Information & Communication Technology
>> University of Malta
>> Web. https://www.um.edu.mt/profile/etiennedepasquale

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