nanog mailing list archives

Re: understanding IPv6


From: "Pascal Thubert \(pthubert\) via NANOG" <nanog () nanog org>
Date: Sun, 7 Jun 2020 19:05:53 +0000

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,

Pascal

Le 7 juin 2020 à 21:00, Joel Halpern <jmh () 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 () monmotha net <mailto:lists.nanog () 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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