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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