Re: [v6ops] new draft: draft-yc-v6ops-solicited-ra-unicast

[Jen Linkova <[e-mail]>]

On Wed, Jul 22, 2015 at 2:12 PM, Alexandru Petrescu
<[e-mail]> wrote:
>
> "... on Androids and iPhones"?
>
> But not on huawei E392.

I'm not sure what the fact that huawei E392 is not affected by a
particular issue proves.
So far we know that
- there are platforms affected;
- there is one unaffected platform.

Therefore I believe it is perfectly find for the title to be 'Reducing
battery impact of Router Advertisements'. If a particular network and
its devices are not affected - good, the network administrators MAY
(or SHOULD?) ignore the draft and not apply the recommendations.

> Le 22/07/2015 14:10, Lorenzo Colitti a écrit :
>>
>> I'm told the problem affects iPhones as well.
>>
>> On Wed, Jul 22, 2015 at 2:07 PM, Alexandru Petrescu
>> <[e-mail] <mailto:[e-mail]>> wrote:
>>
>>     "Reducing battery impact of RAs on Androids"?
>>
>>     Alex
>>
>>     Le 22/07/2015 12:22, Lorenzo Colitti a écrit :
>>
>>         Thanks for all the feedback. We have posted a -01 addressing
>>         some of the
>>         feedback we got. The new version also contains a new
>>         recommendation not
>>         to send periodic RAs too frequently, so we have changed the title to
>>         "Reducing battery impact of Router Advertisements".
>>
>>         https://tools.ietf.org/html/draft-yc-v6ops-solicited-ra-unicast-01
>>
>>         If there are no objections, we will upload this as a WG document
>>         in the
>>         next few days.
>>
>>         On Wed, Jul 22, 2015 at 5:09 AM, Alejandro Acosta
>>         <[e-mail]
>>         <mailto:[e-mail]>
>>         <mailto:[e-mail]
>>         <mailto:[e-mail]>>>
>>         wrote:
>>
>>              Hi There,
>>                 I also support this document, it's very positive to see
>>         that this
>>              algorithm will save energy.
>>
>>              Regards,
>>
>>              Alejandro,
>>
>>              El 7/21/2015 a las 6:11 PM, Nabil Benamar escribió:
>>
>>                  Hi Folks,
>>
>>                  I support this document which is very informative,
>>             useful and its
>>                  implementation will certainly reduce energy consumption
>>             due to
>>                  excessive Multicast RA sent. The proposed algorithm
>>             seems to be
>>                  suitable for this end !
>>
>>
>>                  Best regards
>>
>>
>>
>>                  On Tue, Jul 21, 2015 at 4:38 PM, Owen DeLong
>>             <[e-mail] <mailto:[e-mail]>
>>                  <mailto:[e-mail] <mailto:[e-mail]>>> wrote:
>>
>>                      It seems to me that the following algorithm would be
>>                      relatively easy to implement
>>                      and provide reasonable network optimization…
>>
>>
>>                      On receipt of an RS:
>>
>>                              if(multicast_ra_time_remaining > 15 seconds)
>>                              {
>>                                Send_Unicast_ra
>>                              }
>>                              else
>>                              {
>>                                Send_Multicast_ra
>>                                reset_multicast_timer
>>                              }
>>
>>                      In this way, if the timing is reasonably close, you
>>             multicast
>>                      a packet you were about to send
>>                      anyway, but if the timing isn’t close, you’re not
>>             wasting
>>                      multicast bandwidth answering a single
>>                      node where nobody else cares.
>>
>>                      Overall, I’ve always thought that multicast
>>             response to RS was
>>                      kind of silly. It’s probably most
>>                      harmful on WiFi.
>>
>>                      Owen
>>
>>                      > On Jul 21, 2015, at 02:33 , Andrew Yourtchenko
>>                      <[e-mail] <mailto:[e-mail]>
>>             <mailto:[e-mail] <mailto:[e-mail]>>> wrote:
>>                      >
>>                      > On 7/20/15, Erik Nordmark
>>                      <<mailto:[e-mail]
>>             <mailto:[e-mail]>>[e-mail]
>>             <mailto:[e-mail]>
>>
>>                      <mailto:[e-mail]
>>             <mailto:[e-mail]>>> wrote:
>>                      >> On 7/17/15 9:34 AM, Fred Baker (fred) wrote:
>>                      >>>> So the next logical thing to do would be to
>>             have the
>>                      router default to
>>                      >>>> unicast Router Advertisements, measure the rate of
>>                      received Router
>>                      >>>> Solicitations, and switch to multicast RA mode
>>             past a certain
>>                      >>>> threshold to cover this sort of situation.
>>             Once the
>>                      number of RSes
>>                      >>>> falls, it switches back to unicast RA mode.
>>                      >>>>
>>                      >>>> That would get rid of the configuration knob
>>             proposed in
>>                      this ID, and
>>                      >>>> is behaviour that I think could be universal
>>             for all link
>>                      types,
>>                      >>>> rather than just for the case of wireless ones
>>             with
>>                      mobile devices.
>>                      >>> If it were me implementing it, I think I would
>>             go about
>>                      this in a little
>>                      >>> different way, hopefully simpler. I would want
>>             to send at
>>                      most one (e.g.,
>>                      >>> either zero or one) RA per some interval (a
>>             second?). In
>>                      the normal case,
>>                      >>> that is sent unicast. However, having sent a
>>             unicast RA at
>>                      time t, if I
>>                      >>> now receive another RS before t+1, I send the
>>             next one (at
>>                      time t+1) as a
>>                      >>> multicast.
>>                      >>
>>                      >> First of all I support this document as a WG
>>             document.
>>                      >>
>>                      >> But in terms of implementation, isn't it simpler to
>>                      always(*) respond to
>>                      >> a RS with a unicast RA?
>>                      >
>>                      > Yes. I did not respond on-list yet - but from
>>             operational
>>                      perspective
>>                      > "always send solRA unicast" / "always send solRA
>>             multicast"
>>                      definitely
>>                      > wins in my book, and I'd avoid premature
>>             optimizations (but
>>                      maybe we
>>                      > can say the implementers are explicitly free to
>>             do their own
>>                      > optimizations if they see fit)
>>                      >
>>                      > That said, will be very interesting to hear data
>>             from folks
>>                      who will
>>                      > run "all-unicast solRA", in real networks and
>>             then compare
>>                      the effect
>>                      > of their proposal optimizations on their
>>             real-world scenarios.
>>                      >
>>                      >> As background, the text in RFC4861 comes from
>>             the old
>>                      concern that all
>>                      >> devices might boot at the same time when the
>>             power is
>>                      re-established
>>                      >> after a building power failure; that doesn't
>>             happen since
>>                      most devices
>>                      >> (laptops, smartphones, IoT devices) have
>>             batteries today.
>>                      In that case
>>                      >> it might have made sense to sending fewer RA
>>             messages by
>>                      using multicast.
>>                      >>
>>                      >> (*) the only case in RFC 4861 when I think a
>>             multicast
>>                      response might be
>>                      >> considered is when the source IPv6 address in
>>             the RS is the
>>                      unspecified
>>                      >> address. Further, an implementation which rate
>>             limits
>>                      received RS
>>                      >> packets (e.g., CoPP in a router) might also want
>>             to detect
>>                      when the rate
>>                      >> limit might have dropped RS packets and
>>             multicast an RA in
>>                      that case.
>>                      >>
>>                      >>
>>                      >> I do wonder why implementations haven't already
>>             changed to
>>                      send unicast
>>                      >> solicited RA, and whether it would make a
>>             difference if we
>>                      have an
>>                      >
>>                      > TBH that's my concern as well. I think we should
>>             tweak the
>>                      text in
>>                      > 4861 to encourage a bit more consideration on the
>>                      implementer's side.
>>                      >
>>                      >> informational document asking them to do this.
>>                      Alternatively we could
>>                      >> have a proposed standard which updates section
>>             6.2.6 to
>>                      change the "MAY
>>                      >> unicast" to a "SHOULD unicast".
>>                      >
>>                      > Yeah, I actually have had the different text
>>             aimed for 6man, but
>>                      > Lorenzo's concern was 6man would say "there is no
>>             protocol
>>                      update
>>                      > here, go away", so he rewrote it for v6ops.
>>                      >
>>                      > We should probably discuss this at the mic and
>>             get the
>>                      opinion of the
>>                      > 6man chairs - if there is no outright "no" on this, a
>>                      normative doc
>>                      > would be a better way to convince the implementers ?
>>                      >
>>                      >>
>>                      >> FWIW the draft incorrectly refers to section
>>             6.2.4 instead
>>                      of 6.2.6.
>>                      >
>>                      > Nice catch, thanks!
>>                      >
>>                      > --a
>>                      >
>>                      >>
>>                      >> Thanks,
>>                      >>    Erik
>>                      >>
>>                      >>>
>>                      >>>
>>                      >>> _______________________________________________
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>>             <mailto:[e-mail] <mailto:[e-mail]>>
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>>                      >>
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-- 
SY, Jen Linkova aka Furry