Agree. Erik has made some very good points. I don¹t see a need for extending the ND I-D further. The core protocol should be simple enough and that will suit most use cases. However if Pascal has this special use case and applicability, he could write another I-D explicitly for that purpose. I see no reason to include Pascal's proposed enhancements in the 6lowpan ND I-D.
-Raj On 4/26/11 12:15 AM, "ext Pete St. Pierre" <[email protected]> wrote: >Geoff - >I think Erik has made some very good points on this topic. I don't see a >need to make the ND draft any more complex than it already is. > >...Pete > >On Apr 21, 2011, at 12:42 PM, Geoff Mulligan wrote: > >> Pascal, >> I couple of people supporting the TID is not group consensus. We have >> had many presentations and discussions about multiple LBRs, backbone >> LBRs and more and none have met with the support of the working group. >> >> In your opinions we are crashing, but I fail to see that this is the >> opinion of the working group. >> >> If there are other in the working group that strongly advocate this TID >> idea or the work on multiple and backbone LBRs then they need to speak >> up now en masse or we must move on. >> >> geoff >> >> >> On Thu, 2011-04-21 at 21:32 +0200, Pascal Thubert (pthubert) wrote: >>> Geoff: >>> >>> There is twice as much support for restoring the TID than there is for >>> not doing it. >>> Before we drop the TID, I'd like to see a proposal that allows a >>>6LoWPAN ND subnet to scale with multiple LBRs, allows nodes to move >>>from a router to the next, and that does not need a TID. >>> Otherwise, we are not speeding towards the wall, we're already >>>crashing. >>> >>> Pascal >>> http://www.xtranormal.com/watch/7011357/ >>> >>>> -----Original Message----- >>>> From: Geoff Mulligan [mailto:[email protected]] >>>> Sent: Thursday, April 21, 2011 5:41 PM >>>> To: Pascal Thubert (pthubert) >>>> Cc: Erik Nordmark; [email protected]; >>>>[email protected] >>>> Subject: Re: [6lowpan] FW: TID in ARO [was: "Advertize on Behalf" >>>>flag in >>>> ARO] >>>> >>>> Pascal, >>>> We need to close on this discussion. >>>> >>>> Back in Hiroshima the Working Group decided that Backbone router >>>>stuff and >>>> "address defense" across backbone routers was not going to be part of >>>>ND >>>> draft. It appeared that the draft was getting way to complicated and >>>>the >>>> Working Group decided to simplify things. >>>> >>>> I have not seen much support on the list for making these changes to >>>>include >>>> the TID in ND. >>>> >>>> We need to get this draft completed. If there is a large "unheard >>>>from" >>>> support group for these changes, please speak up or we shall move >>>>forward >>>> with the draft as it is. >>>> >>>> geoff >>>> >>>> >>>> >>>> >>>> On Thu, 2011-04-21 at 09:27 +0200, Pascal Thubert (pthubert) wrote: >>>>> Hi Erik >>>>> >>>>> The TID is not a strong coupling between the H2R and the R2R >>>>>operations, >>>> and it is not a coupling with a RPL version explicitly. >>>>> It is an abstract information that if defined properly can be used >>>>>by many >>>> forms or R2R interactions. >>>>> As demonstrated by older versions of the ND spec (Backbone Router), >>>>>RPL, >>>> and MIP. >>>>> >>>>> 6LoWPAN ND cannot scale if the node needs to register to all LBRs. >>>> 6LoWPAN ND does not define anymore any LBR interaction. >>>>> IOW, 6LoPWAN ND lost the capability to scale when the backbone router >>>> piece was removed from the draft. >>>>> Which means that it lost its capability to apply in the domains I'm >>>>>looking at >>>> (industrial and metering). >>>>> >>>>> With the TID, we know that we can restore scalability in the future, >>>>>and we >>>> know how. I do not know of a plan B. >>>>> >>>>> Pascal >>>>> http://www.xtranormal.com/watch/7011357/ >>>>> >>>>> >>>>>> -----Original Message----- >>>>>> From: Erik Nordmark [mailto:[email protected]] >>>>>> Sent: Thursday, April 21, 2011 1:25 AM >>>>>> To: [email protected] >>>>>> Cc: Pascal Thubert (pthubert); [email protected]; Dijk, Esko >>>>>> Subject: Re: [6lowpan] FW: TID in ARO [was: "Advertize on Behalf" >>>>>> flag in ARO] >>>>>> >>>>>> On 4/20/11 1:21 AM, [email protected] wrote: >>>>>>> >>>>>>> Dear Pascal and al, >>>>>>> >>>>>>> I support the idea of reviving the TID in ARO and DAR/DAC. >>>>>>> Supporting a TID directly in the node initiating the initial NS >>>>>>> appears much simpler than time stamping in the parent router. >>>>>> >>>>>> How would you make this work if the protocol between the routers is >>>>>> not RPLv1, but some future version of RPL or a completely different >>>>>> routing protocol? >>>>>> >>>>>> The decoupling of the host-router interaction from router-router >>>>>> interaction has served us well in the history of the Internet. >>>>>> >>>>>> Erik >>>>>> >>>>>>> A simple and efficient method to detect mobility of hosts along a >>>>>>> backbone of Edge Routers is an important feature to deploy >>>>>>> backbones of Edge Routers in Buildings and should be clarified >>>>>>> before closing 6LoWPAN WG. >>>>>>> >>>>>>> Cheers, >>>>>>> Nicolas >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> *"Pascal Thubert (pthubert)" <[email protected]>* Envoyé par : >>>>>>> [email protected] >>>>>>> >>>>>>> 18/04/2011 10:37 >>>>>>> >>>>>>> >>>>>>> A >>>>>>> "Dijk, Esko" <[email protected]>, "Erik Nordmark" >>>>>>> <[email protected]> cc >>>>>>> [email protected] >>>>>>> Objet >>>>>>> Re: [6lowpan] FW: TID in ARO [was: "Advertize on Behalf" flag >>>>>>>in >>>>>> ARO] >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> Hi Esko, Erik >>>>>>> >>>>>>> The discussion on RPL and hosts should happen on the RPL list >>>>>>> under a different topic. The point being discussed here is this: >>>>>>> >>>>>>> The reality is also that those (LLN) networks will need to scale >>>>>>> to large subnets in plants, building, etc... (see the requirement >>>>>>> drafts in ROLL). Registering to all LBRS is totally impractical. >>>>>>> 6LoWPAN ND requires a coordination between LBRs but does not say >>>> how it happens. >>>>>>> This problem was discussed in 6LoWPAN; the answer was in >>>>>>> ND-01to07; and it requires a TID, for the same reason as RPL. >>>>>>> Removing the backbone operation and the TID from the draft is >>>>>>>ostrich >>>> policy. >>>>>>> >>>>>>> BTW 6LoWPAN ND needs a TID to correlate the NS and the NA as all >>>>>>> other registrations do when strict ordering is not guaranteed (MIP >>>>>>> being an example). Say that due to some config, a node registers a >>>>>>> lifetime of X, then deregisters (lifetime 0), then reregisters >>>>>>> (lifetime X) in a rapid sequence, but does not get an answer yet. >>>>>>> Then it finally gets 2 AROs back, lifetime X and 0. What's the >>>>>>>final state >>>> in the router? >>>>>>> >>>>>>> I'd like to hear what others think. >>>>>>> >>>>>>> Pascal >>>>>>> http://www.xtranormal.com/watch/7011357/ >>>>>>> >>>>>>> >>>>>>>> -----Original Message----- >>>>>>>> From: Dijk, Esko [mailto:[email protected]] > Sent: >>>>>>> Monday, April 18, 2011 10:19 AM > To: Erik Nordmark; Pascal >>>>>>> Thubert >>>>>>> (pthubert) > Cc: [email protected] > Subject: RE: [6lowpan] FW: >>>>>>> TID in ARO [was: "Advertize on Behalf" flag in > ARO] > > Hello >>>>>>> Erik, >>>>>>>>> taking the definition you quoted: >>>>>>>> 'host' refers to an LLN device that can generate but does not >>>>>>> forward > RPL traffic > > the question may arise what is "RPL >>>>>>> traffic"? It is not defined in the RPL draft > it seems. Pascal >>>>>>> clarified to me it is traffic associated to a RPL instance, not > >>>>>>> necessarily RPL protocol messages. This means that a host could >>>>>>> generate > RPL traffic without being aware of the existence of >>>>>>> RPL at all. So, _not_ all > hosts have to speak RPL? >>>>>>>> The RPL draft does not explicitly state if "hosts" in a RPL >>>>>>> network always > speak RPL, never speak RPL, or can be mixed >>>>>>> RPL/non-RPL speakers. >>>>>>>> >>>>>>>> Taking the definition of 'node' in the RPL draft: >>>>>>>> 'node' refers to any RPL device, either a host or a router > >>>>>>>> rules out (?) the option that all "hosts" are non-RPL speakers, >>>>>>> since there > may be a "RPL device" (i.e. RPL-speaking device, I >>>>>>> assume) that is also a host. >>>>>>>> >>>>>>>> I communicated these perceived unclarities to Pascal and the >>>>>>> RFC editor 2 > weeks ago. Once this is clear I think the present >>>>>>> discussion can continue. >>>>>>>> And then there is the related discussion of ND support for >>>>>>> sleepy devices, > the original topic of Anders ;) > > best >>>>>>> regards, > > Esko > > > > -----Original Message----- > From: >>>>>>> [email protected] [mailto:[email protected]] On > >>>>>>> Behalf Of Erik Nordmark > Sent: Friday 15 April 2011 18:39 > To: >>>>>>> Pascal Thubert (pthubert) > Cc: [email protected] > Subject: Re: >>>>>>> [6lowpan] FW: TID in ARO [was: "Advertize on Behalf" flag in > >>>>>>> ARO] >>>>>>>>> On 4/14/11 11:43 PM, Pascal Thubert (pthubert) wrote: >>>>>>>> >>>>>>>>> RPL can do what all classical IGPs can do WRT hosts. That is >>>>>>> as long > > as the host address belongs to the router's prefix >>>>>>> and stays attached > > to that router. >>>>>>>> >>>>>>>> I just realized that we might be talking about a different >>>>>>> definition of "host". >>>>>>>> What I mean by "host" is a node which does not participate in a >>>>>>> routing > protocol, and does not forward packets (except packets >>>>>>> explicitly addressed > to itself using e.g., a routing header). >>>>>>>> >>>>>>>> However, RPL has a different definition: >>>>>>>> 'host' refers to an LLN device that can generate but does not >>>>>>> forward > RPL traffic > > Basically per the RPL definition >>>>>>> there is no such thing as a node which does > not participate in >>>>>>> the RPL protocol. >>>>>>>> IMHO what is in RPL should have been defined as a >>>>>>> non-forwarding node, so > that we can have a sane discussion >>>>>>> without getting entangled in terminology > issues. >>>>>>>> >>>>>>>> Which definition of "host" are you using above? >>>>>>>> >>>>>>>> Per the RPL definition there is no need for 6lowpan-nd, since >>>>>>> all nodes will > speak RPL. This is rather confusing, don't you >>>>>>>think? >>>>>>>> >>>>>>>> Erik >>>>>>>> >>>>>>>>> When the topology becomes multilink subnet and mobility is >>>>>>> required > > then it is a new problem entirely, and NO, 4861 is >>>>>>> not a suitable > > interaction with the router to allow the >>>>>>> router to redistribute a host route. >>>>>>>>> Because the neighbor cache that 4861 builds is not a of the >>>>>>> same >>>>>>>>> nature as the binding table that 6LoWPAN ND builds. Another >>>>>>>>> thing >>>>>>> that > > 6LoWPAN ND fails to express correctly. I proposed text >>>>>>> to explain that > > (attached) but it was not considered, >>>>>>> contributing to the illusion > > that a cache is a table. >>>>>>>>> >>>>>>>>> The reality is also that those networks will need to scale to >>>>>>> large > > subnets in plants, building, etc... (see the >>>>>>> requirement drafts in > > ROLL). Registering to all LBRS is >>>>>>>totally >>>> impractical. >>>>>>> 6LoWPAN ND > > requires a coordination between LBRs but does not >>>>>>> say how it happens. >>>>>>>>> This problem was discussed in 6LoWPAN; the answer was in >>>>>>> ND-01to07; > > and it requires a TID, for the same reason as RPL. >>>>>>> Removing the > > backbone operation and the TID from the draft is >>>>>>> ostrich >>>>>> policy. >>>>>>>>> >>>>>>>>> RPL already adapted to the new reality of large multilink >>>>>>> subnet with > > inner mobility. Placing the blame on RPL is >>>>>>> another illusionist trick. >>>>>>>>> And this is not RPL last call. >>>>>>>>> >>>>>>>>> BTW 6LoWPAN ND needs a TID to correlate the NS and the NA as >>>>>>> all other > > registrations do when strict ordering is not >>>>>>> guaranteed (MIP being an > > example). Say that due to some >>>>>>> config, a node registers a lifetime of > > X, then deregisters >>>>>>> (lifetime 0), then reregisters (lifetime X) in a > > rapid >>>>>>> sequence, but does not get an answer yet. Then it finally gets >>>>>>> 2 >>>>>>>>> AROs back, lifetime X and 0. What's the final state in the >>>>>>>>>router? >>>>>>>>> >>>>>>>>> It seems we can never agree on any of this. I'd like to hear >>>>>>> what >>>>>>>>> others think. >>>>>>>>> >>>>>>>>> Pascal >>>>>>>>> http://www.xtranormal.com/watch/7011357/ >>>>>>>>> >>>>>>>>> >>>>>>>>>> -----Original Message----- >>>>>>>>>> From: [email protected] [mailto:6lowpan- >>>>>> [email protected]] >>>>>>> On > >> Behalf Of Erik Nordmark > >> Sent: Friday, April 15, >>>>>>> 2011 >>>>>>> 1:30 AM > >> To: 6lo>> '6lowpan' >>>>>>>>>> Subject: Re: [6lowpan] Fwd: Re: "Advertize on Behalf" flag >>>>>>> in ARO > >> > >> > >> On 4/13/11 12:53 AM, Pascal Thubert >>>>>>> (pthubert) >>>>>>> wrote: >>>>>>>>>>> Hi Erik: >>>>>>>>>>> >>>>>>>>>>> The RPL (DAO) sequence number allows the node to increment >>>>>>> rapidly > >>> in case of rapid changes and then lazily when the >>>>>>> situation is > >>> stable and DAO are scarce. The increase is >>>>>>> strictly monotonous which > > > >>> is critical to us. >>>>>>>>>>> >>>>>>>>>>> A time stamp imposes a synchronization between the routers. >>>>>>> We do > >>> not have such mechanism in RPL. A time unit (a >>>>>>> granularity) must be > >>> agreed upon. Within that unit, >>>>>>> movements go undetected so the time > >>> unit must be thin >>>>>>>grained >>>> to cover rapid changes. >>>>>>> Yet, depending on > >>> the medium, the time unit, and the size >>>>>>> of the network, it is not > >>> necessarily easy/possible to >>>>>>> guarantee a strictly monotonous value > >>> with a thin grained >>>>>>> time unit. And we have limited space (2 >>>>>>> octets) >>>>>>>>>>> and have to deal with wrap around, which divides the space >>>>>>> by at > > least 3. >>>>>>>>>>> >>>>>>>>>>> So RPL went for a sequence number. >>>>>>>>>> >>>>>>>>>> But the unstated assumption that RPL made is that all >>>>>>> host-to-router > >> protocols have to now be RPL aware. That >>>>>>> doesn't sound like good > > design. >>>>>>>>>> A host isn't aware of whether the routers speak IS-IS or >>>>>>> OSPF, so why > >> do the hosts need to be aware of RPL by passing >>>>>>> some TID around? >>>>>>>>>> >>>>>>>>>>> I think ND has the same need as MIP for a TID == Sequence # . >>>>>>> We > >>> know of MIP; We know of RPL. We know of the backbone >>>>>>> router >>>>>>>>>>> operation. We know we'll need the TID and we know exactly >>>>>>>>>>> why. I think we should have it in the 6LowPAN ND spec right >>>>>>>>>>> away to >>>>>>> avoid > >>> interop issues when we add RPL and BR operations. >>>>>>>>>> >>>>>>>>>> I don't see a need in 6lowpan-nd for a TID; the protocol >>>>>>> works fine > > without it. >>>>>>>>>> I think RPL needs to be improved to deal with reality. Isn't >>>>>>> there a > >> desire for RPL to handle 4861 hosts? Those would >>>>>>> never know about a > > TID. >>>>>>>>>> >>>>>>>>>> Erik >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> 6lowpan mailing list >>>>>>>>>> [email protected] >>>>>>>>>> https://www.ietf.org/mailman/listinfo/6lowpan >>>>>>>>> _______________________________________________ >>>>>>>>> 6lowpan mailing list >>>>>>>>> [email protected] >>>>>>>>> https://www.ietf.org/mailman/listinfo/6lowpan >>>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> 6lowpan mailing list >>>>>>>> [email protected] >>>>>>>> https://www.ietf.org/mailman/listinfo/6lowpan >>>>>>>> >>>>>>>> The information contained in this message may be confidential >>>>>>> and legally > protected under applicable law. The message is >>>>>>> intended solely for the > addressee(s). 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