Re: [Roll] using the flow label instead of hop by hop
Philip Levis <pal@cs.stanford.edu> Tue, 23 October 2012 16:07 UTC
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From: Philip Levis <pal@cs.stanford.edu>
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Date: Tue, 23 Oct 2012 08:41:35 -0700
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To: Pascal Thubert <pthubert@cisco.com>
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Subject: Re: [Roll] using the flow label instead of hop by hop
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What if an end-host outside the RPL instance wants to use a flow label for its own purposes? It might think that a flow denotes a stream of associated packets to a node within a RPL instance, not the OF that instance happens to use. Phil On Oct 23, 2012, at 4:41 AM, Pascal Thubert (pthubert) wrote: > Hi: > > <I answered to John from my phone but then realized that I did not copy the list.> > > In short: The packets carried within an instance share a characteristic which the OF optimizes for. > The OF determines a RPL topology and thus how the flow that is tagged with that instance is processed in the network. > For flows to be processed differently one may different instances. > > Considering how open the definition of flow in 2460 is, this fits. > > The rank stretches that a bit since it qualifies where the flow is in the Network. > Then again RFC 2460 is open enough not to bar anything. > > Rather, the spirit is for us to do something useful with this field in the forwarding plane and that is exactly what this proposal is doing . > > Cheers, > > Pascal > > > -----Original Message----- > From: John E Drake [mailto:jdrake@juniper.net] > Sent: lundi 22 octobre 2012 21:15 > To: Pascal Thubert (pthubert); adrian@olddog.co.uk; roll@ietf.org > Subject: RE: [Roll] using the flow label instead of hop by hop > > Pascal, > > So the information that you are carrying in the IPv6 label field has nothing to do with IPv6 labels? So, why is this not an egregious hack? > > Yours irrespectively, > > John > > >> -----Original Message----- >> From: roll-bounces@ietf.org [mailto:roll-bounces@ietf.org] On Behalf >> Of Pascal Thubert (pthubert) >> Sent: Saturday, October 20, 2012 2:30 PM >> To: adrian@olddog.co.uk; roll@ietf.org >> Subject: Re: [Roll] using the flow label instead of hop by hop >> >> Adrian, >> >> This draft is not mpls. This draft is about carrying the RPL info >> (rank, instance, flags) in the flow label as opposed to the HbH which >> incurs additional header + eventually tunneling. >> My other draft on fragment forwarding has a lot more to do with label >> switching since the first fragment lays a label that the other >> fragments follow. But then we are not using the flow label but a >> 6LoWPAN datagram identifier tag. >> >> Cheers, >> >> Pascal >> >> -----Original Message----- >> From: roll-bounces@ietf.org [mailto:roll-bounces@ietf.org] On Behalf >> Of Adrian Farrel >> Sent: samedi 20 octobre 2012 21:37 >> To: roll@ietf.org >> Subject: Re: [Roll] using the flow label instead of hop by hop >> >> Speaking as an individual and without an implementation... >> >> Isn't this MPLS? >> Hasn't the routing area looked at the idea of using the IPv6 flow >> label for labelled forwarding more than once in the past? >> Hasn't the conclusion always been that you could do it, but you would >> have to be sure that you were not overloading the field? >> And hasn't the resulting discussion led to a debate on the value of >> label stacks and the impracticality of label stacks using the flow >> label? >> >> Cheers, >> Adrian >> >>> -----Original Message----- >>> From: roll-bounces@ietf.org [mailto:roll-bounces@ietf.org] On Behalf >>> Of Philip Levis >>> Sent: 20 October 2012 14:50 >>> To: Pascal Thubert (pthubert) >>> Cc: roll@ietf.org >>> Subject: Re: [Roll] using the flow label instead of hop by hop >>> >>> On Oct 20, 2012, at 1:19 AM, Pascal Thubert (pthubert) wrote: >>> >>>> Phil; >>>> >>>> There is indeed lot of pressure for this in terms of header sizes >>>> and energy >>> consumption in the *real world*. >>> >>> I'm personally concerned about header sizes and energy consumption >>> in The Matrix. Because I don't live in the real world. Oh, wait, >>> sorry, >> I >>> do. Can you >> walk >>> me through the quantitative reasoning that a few bytes of header >>> will increase energy consumption? It the belief that it will lead to >>> sub-packet >> fragmentation in >>> some non-amortized sense? Generally speaking, in low power wireless >>> networks, energy consumption is dominated by idle listening and >>> communication latency/interval support, not the length of packets. >>> Of course there is a >> spectrum >>> of low power approaches and their point on that spectrum. Are you >>> thinking of one in particular? >>> >>> Could implementers who are encountering this pressure comment? I'm a >>> sucker for and easily swayed by quantitative data as well as >>> first-hand rather than second-hand reports. >>> >>>> And there is no hack in the proposed solution. >>>> Simply we believe more in practical engineering and ML discussions >>>> than we >>> trust in crystal balls. >>> >>> *coughs politely* I believe in very practical engineering that >>> considers long >> term >>> consequences. Solving a problem a certain way now might cause >>> significant problems in the future. I agree this is a tradeoff -- in >>> my personal opinion, >> nothing >>> more, the tradeoff on this one is 100% clear. >>> >>> Phil >>> >>> ------ >>> >>> Philip Levis >>> President, Kumu Networks >>> Associate Professor, Stanford University >>> http://csl.stanford.edu/~pal >>> _______________________________________________ >>> Roll mailing list >>> Roll@ietf.org >>> https://www.ietf.org/mailman/listinfo/roll >> >> _______________________________________________ >> Roll mailing list >> Roll@ietf.org >> https://www.ietf.org/mailman/listinfo/roll >> _______________________________________________ >> Roll mailing list >> Roll@ietf.org >> https://www.ietf.org/mailman/listinfo/roll > > > _______________________________________________ > Roll mailing list > Roll@ietf.org > https://www.ietf.org/mailman/listinfo/roll
- [Roll] using the flow label instead of hop by hop Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Abdussalam Baryun
- Re: [Roll] using the flow label instead of hop by… Owen Kirby
- Re: [Roll] using the flow label instead of hop by… Philip Levis
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Philip Levis
- Re: [Roll] using the flow label instead of hop by… Adrian Farrel
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… John E Drake
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… John E Drake
- Re: [Roll] using the flow label instead of hop by… Philip Levis
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Philip Levis
- Re: [Roll] using the flow label instead of hop by… Brian E Carpenter
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Ralph Droms
- Re: [Roll] using the flow label instead of hop by… Brian E Carpenter
- Re: [Roll] using the flow label instead of hop by… Ralph Droms
- Re: [Roll] using the flow label instead of hop by… Adrian Farrel
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Michael Richardson
- Re: [Roll] using the flow label instead of hop by… Michael Richardson
- Re: [Roll] using the flow label instead of hop by… Adrian Farrel
- Re: [Roll] using the flow label instead of hop by… John E Drake
- Re: [Roll] using the flow label instead of hop by… Philip Levis
- Re: [Roll] using the flow label instead of hop by… Brian E Carpenter
- Re: [Roll] using the flow label instead of hop by… Michael Richardson
- Re: [Roll] using the flow label instead of hop by… Philip Levis
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Carsten Bormann
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Philip Levis
- Re: [Roll] using the flow label instead of hop by… Pascal Thubert (pthubert)
- Re: [Roll] using the flow label instead of hop by… Philip Levis