Re: [ipwave] Fwd: New Version Notification for draft-ietf-ipwave-ipv6-over-80211ocb-31.txt

Hi All,

I support John’s comment. ITS-G5/DSRC/OCB can fully do unicast with acks. It is the application that chose not to use this but rather broadcast. And even considering broadcast, I do not think we have higher packet losses. Just that we do not retransmit, as it is broadcast. Maybe we should mention reduced ‘application-layer reliability’ so something in that direction..

BR,

Jérôme 

From: its [mailto:its-bounces@ietf.org] On Behalf Of John Kenney
Sent: Tuesday 04 December 2018 16:38
To: Alexandre Petrescu
Cc: its; Dorothy Stanley
Subject: Re: [ipwave] Fwd: New Version Notification for draft-ietf-ipwave-ipv6-over-80211ocb-31.txt

Hi,

Caveat: I know nothing about Neighbor Discovery protocol.

I see this in the proposed new text: 

Due to lack of link-layer acknowledgements in 802.11-OCB, we can expect higher packet loss than for 802.11 BSS. 

I don't understand why it is expected that OCB has a lack of link-layer acknowledgments.  OCB uses link layer acks the same way as 802.11 BSS uses them.   If I send a unicast 802.11 packet outside the context of a BSS, I expect an 802.11 ACK. If I don't get the 802.11 ACK, I go through exponential backoff and retransmit.  Just like normal 802.11.  Maybe I'm missing something.

Best Regards,

John

On Tue, Dec 4, 2018 at 7:11 AM Alexandre Petrescu <alexandre.petrescu@gmail.com> wrote:

Le 04/12/2018 à 16:04, Dorothy Stanley a écrit :
> Hello Alexandre, all,
> 
> I am sharing the following information from John Kenny ( 
> jkenney@us.toyota-itc.com <mailto:jkenney@us.toyota-itc.com>), who is
> actively involved in 802.11p implementation and deployments: "OCB can
> use unicast in the same way as other flavors of 802.11 ( individually
> addressed 802.11 MAC PDU that is ACKed using 802.11 procedures ). I
> find this is a common misunderstanding (indeed, I am in a meeting
> right now where this very point came up about 20 minutes ago).
> Probably the confusion is partly due to the fact that a great deal of
> DSRC attention is focused on the broadcast Basic Safety Message. Some
> people think that DSRC is only BSMs, or only broadcast messages. But,
> there are some important unicast applications as well."
> 
> Thus a change is needed in 4.7, either delete the second sentence or
>  modify to reflect that unicast is acknowledged.

I propose

NEW:
> The Neighbor Discovery protocol (ND) [RFC4861] is used over 
> 802.11-OCB links.  Due to lack of link-layer acknowledgements in 
> 802.11-OCB, we can expect higher packet loss than for 802.11 BSS. The
> ND retransmissions are supposed to handle loss of IP unicast and/or 
> IP multicast just as it does for other link types.

(remark disappeared 'unicast' and 'multicast' from 2nd phrase, and added 
'IP' in front of unicast and multicast in 3rd phrase).

OLD:
> The Neighbor Discovery protocol (ND) [RFC4861] is used over 
> 802.11-OCB links.  Due to lack of link-layer acknowledgements in 
> 802.11-OCB for both unicast and multicast, we can expect higher 
> unicast loss than for 802.11 BSS.  The ND retransmissions are 
> supposed to handle loss of unicast and/or multicast just as it does 
> for other link types.

Would this be agreed by John Kenney.

Alex

> 
> Thanks,
> 
> Dorothy
> 
> ---------------------- Dorothy Stanley IEEE 802.11 WG Chair, 
> dstanley@ieee.org <mailto:dstanley@ieee.org> Hewlett Packard 
> Enterprise dorothy.stanley@hpe.com 
> <mailto:dstanley@arubanetworks.com> dstanley1389@gmail.com 
> <mailto:dstanley1389@gmail.com> +1 630-363-1389 <tel:630-363-1389>
> 
> 
> 
> On Mon, Nov 19, 2018 at 10:07 AM Alexandre Petrescu 
> <alexandre.petrescu@gmail.com <mailto:alexandre.petrescu@gmail.com>>
>  wrote:
> 
> Hi IPWAVErs,
> 
> Following the discussion during presentation of the IPv6/OCB slides 
> by Nabil during IPWAVE WG meeting, I have updated the IPv6/OCB 
> draft.
> 
> This is the ChangeLog:
> 
> - filled in the section titled "Pseudonym Handling"; - removed a 'MAY
> NOT' phrase about possibility of having other prefix than the LL on
> the link between cars; - shortened and improved the paragraph about
> Mobile IPv6, now with DNAv6; - improved the ND text about ND 
> retransmissions with relationship to packet loss; - changed the title
> of an appendix from 'EPD' to 'Protocol Layering'; - improved the
> 'Aspects introduced by OCB' appendix with a few phrases about the
> channel use and references.
> 
> This fixes all issues about ND and pseudonym handling.
> 
> Alex
> 
> -------- Message transféré -------- Sujet : New Version Notification
>  for draft-ietf-ipwave-ipv6-over-80211ocb-31.txt Date : Mon, 19 Nov 
> 2018 10:01:52 -0800 De : internet-drafts@ietf.org 
> <mailto:internet-drafts@ietf.org> Pour : Jerome Haerri 
> <Jerome.Haerri@eurecom.fr <mailto:Jerome.Haerri@eurecom.fr <mailto:Jerome.Haerri@eurecom..fr> >>, 
> ipwave-chairs@ietf.org <mailto:ipwave-chairs@ietf.org>, Jerome Haerri
> <jerome.haerri@eurecom.fr <mailto:jerome.haerri@eurecom.fr <mailto:jerome.haerri@eurecom..fr> >>, 
> Alexandre Petrescu <Alexandre.Petrescu@cea.fr 
> <mailto:Alexandre.Petrescu@cea.fr>>, Alexandre Petrescu 
> <alexandre.petrescu@cea.fr <mailto:alexandre.petrescu@cea.fr>>, Nabil
> Benamar <n.benamar@est.umi.ac.ma <mailto:n.benamar@est.umi.ac.ma>>,
> Thierry Ernst <thierry.ernst@yogoko.fr
> <mailto:thierry.ernst@yogoko.fr>>, Jong-Hyouk Lee
> <jonghyouk@smu.ac.kr <mailto:jonghyouk@smu.ac.kr>>
> 
> 
> A new version of I-D, draft-ietf-ipwave-ipv6-over-80211ocb-31.txt has
> been successfully submitted by Alexandre Petrescu and posted to the
> IETF repository.
> 
> Name:           draft-ietf-ipwave-ipv6-over-80211ocb Revision: 31 
> Title:          Transmission of IPv6 Packets over IEEE 802.11 
> Networks operating in mode Outside the Context of a Basic Service Set
> (IPv6-over-80211-OCB) Document date:  2018-11-19 Group: ipwave Pages:
> 41 URL: 
> https://www.ietf.org/internet-drafts/draft-ietf-ipwave-ipv6-over-80211ocb-31.txt
>
>
>
> 
Status:
> https://datatracker.ietf.org/doc/draft-ietf-ipwave-ipv6-over-80211ocb/
>
>
>
> 
Htmlized:
> https://tools.ietf.org/html/draft-ietf-ipwave-ipv6-over-80211ocb-31 
> Htmlized: 
> https://datatracker.ietf.org/doc/html/draft-ietf-ipwave-ipv6-over-80211ocb
>
>
>
> 
Diff:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-ipwave-ipv6-over-80211ocb-31
>
>
>
> 
Abstract: In order to transmit IPv6 packets on IEEE 802.11 networks
> running outside the context of a basic service set (OCB, earlier 
> "802.11p") there is a need to define a few parameters such as the 
> supported Maximum Transmission Unit size on the 802.11-OCB link, the
>  header format preceding the IPv6 header, the Type value within it, 
> and others.  This document describes these parameters for IPv6 and 
> IEEE 802.11-OCB networks; it portrays the layering of IPv6 on 
> 802.11-OCB similarly to other known 802.11 and Ethernet layers - by 
> using an Ethernet Adaptation Layer.
> 
> 
> 
> 
> 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 <http://tools.ietf.org>.
> 
> The IETF Secretariat
> 
> _______________________________________________ its mailing list 
> its@ietf.org <mailto:its@ietf.org> 
> https://www.ietf.org/mailman/listinfo/its
> 

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John Kenney

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