Carlos, yes, and thanks for the review. Regards Lizhong > -----Original Message----- > From: Carlos Pignataro (cpignata) [mailto:cpignata@xxxxxxxxx] > Sent: 2014年10月23日 22:29 > To: Lizhong Jin > Cc: Joel Halpern Direct; mpls@xxxxxxxx; gen-art@xxxxxxxx; draft-ietf-mpls-lsp- > ping-relay-reply.all; ietf@xxxxxxxx > Subject: Re: [mpls] [Gen-art] review: draft-ietf-mpls-lsp-ping-relay-reply-04 > > Hi Lizhong, > > Please also take into consideration the Ops Dir review of this doc, in which I > have similar concerns as those from Joel. > > There seem to be three major areas in discussion: > 1. The scope of the problem being solved (i.e., which cases are solved, which > are not, and which are the common cases) 2. The mechanism itself not > working in many cases. > 3. How this all works with IPv6 addresses (since your fix seems to cover the > overlapping IPv4 private address case only) > > Thanks, > > Carlos. > > > On Oct 22, 2014, at 10:05 AM, lizho.jin@xxxxxxxxx wrote: > > > > Joel, thank you for the review. We will send out a new version soon to > reflect the discussion. > > > > Regards > > Lizhong > > > > > > > >> 在 2014年10月22日，下午9:30，Joel Halpern Direct > <jmh.direct@xxxxxxxxxxxxxxx> > >> wrote： > >> > >> It would be good to see a revision that clearly spelled out what the > >> draft was solving, how the initial end-point knew what to create, and > >> how the responder knew what to use. It may well be that there is an > >> effective solution to the problems here. I look forward to seeing it > >> in writing. > >> > >> Yours, > >> Joel > >> > >>> On 10/22/14, 12:46 AM, Lizhong Jin wrote: > >>> Hi Joel, > >>> The things may not be that bad. You could add a second address > >>> (address B in our example) with K bit set. The address entry with K > >>> bit set must be as a relay node, and could not be skipped. > >>> Section 4.4 should be changed to: Find the first routable address A, > >>> and the first address B with K bit set. If address A is before > >>> address B in the stack, then use address B as the relay address. > >>> Otherwise, use address A as the relay address. > >>> In that case, if A is the private address, the packet will be > >>> firstly relayed to address B. And address A and B belong to one > >>> router. Here I assume one router at least has one routable address for > another AS. > >>> > >>> Regards > >>> Lizhong > >>> > >>>> -----Original Message----- > >>>> From: Joel M. Halpern [mailto:jmh@xxxxxxxxxxxxxxx] > >>>> Sent: 2014年10月22日 11:14 > >>>> To: Lizhong Jin > >>>> Cc: gen-art@xxxxxxxx; mpls@xxxxxxxx; ietf@xxxxxxxx; > >>> 'draft-ietf-mpls-lsp-ping- > >>>> relay-reply.all' > >>>> Subject: Re: [mpls] [Gen-art] review: > >>> draft-ietf-mpls-lsp-ping-relay-reply-04 > >>>> > >>>> ou are saying that this is only for the case where an AS is using > >>>> public addresses for its internal numbering, but is not > >>>> distributing that address > >>> block > >>>> externally? > >>>> > >>>> If so, you need to state that very clearly. > >>>> I believe a far more common case is one where the numbering is from > >>>> a portion of a publicly allocated space, but firewalled. Which > >>>> would > >>> produce > >>>> the same problem, but would not be amenable to this solution. > >>>> And it is well known that many ISPs do internal number assignment > >>>> from private blocks. > >>>> > >>>> So what you are now saying is that this draft solves a very small > >>>> portion > >>> of the > >>>> problem? But it works for that small portion? If so, at the very > >>>> least > >>> you > >>>> need to be VERY clear about what cases this works for and what > >>>> cases it > >>> does > >>>> not. And I fear that even if you are clear, it is going to be very > >>> confusing for > >>>> folks who are trying to use it. > >>>> > >>>> Yours, > >>>> Joel > >>>> > >>>>> On 10/21/14, 10:51 PM, Lizhong Jin wrote: > >>>>> Hi Joel, > >>>>> I now see your concern. The "private" word in draft is not > >>>>> correct, I will remove it. The original motivation of > >>>>> "draft-relay-reply" is from the scenario where IP address > >>>>> distribution is restricted among AS or IGP > >>>> area. > >>>>> And the IP address is not private address. As I know, most > >>>>> deployed inter-AS or inter-area MPLS LSP is in the network without > >>>>> private IP > >>> address. > >>>>> > >>>>> Regards > >>>>> Lizhong > >>>>> > >>>>> > >>>>>> -----Original Message----- > >>>>>> From: Joel M. Halpern [mailto:jmh@xxxxxxxxxxxxxxx] > >>>>>> Sent: 2014年10月22日 10:15 > >>>>>> To: Lizhong Jin > >>>>>> Cc: gen-art@xxxxxxxx; mpls@xxxxxxxx; ietf@xxxxxxxx; > >>>>> 'draft-ietf-mpls-lsp-ping- > >>>>>> relay-reply.all' > >>>>>> Subject: Re: [mpls] [Gen-art] review: > >>>>> draft-ietf-mpls-lsp-ping-relay-reply-04 > >>>>>> > >>>>>> The problem is that the original source A, that we are trying to > >>>>>> reach > >>>>> with a > >>>>>> reply, has an address that appears to the responder X to be routable. > >>>>>> But the destination that is reached by that address is either a > >>>>>> black hole or > >>>>> some > >>>>>> other entity using the same address. > >>>>>> > >>>>>> The reason for the duplication is that, as described in the > >>>>>> draft, the > >>>>> source > >>>>>> address for A is a private address. That same address may well > >>>>>> be > >>>>> reachable > >>>>>> according to the routing table at X. But it won't get to A. > >>>>>> > >>>>>> If the problem is something other than private addressing > >>>>>> preventing reachability, it is likely there is still a mistaken > >>>>>> routability problem, > >>>>> but I can > >>>>>> not illustrate the failure without some other case being described. > >>>>>> > >>>>>> Yours, > >>>>>> Joel > >>>>>> > >>>>>>> On 10/21/14, 10:06 PM, Lizhong Jin wrote: > >>>>>>> Inline, thanks. > >>>>>>> > >>>>>>>> -----Original Message----- > >>>>>>>> From: Joel M. Halpern [mailto:jmh@xxxxxxxxxxxxxxx] > >>>>>>>> Sent: 2014年10月22日 0:06 > >>>>>>>> To: lizho.jin@xxxxxxxxx > >>>>>>>> Cc: gen-art@xxxxxxxx; mpls@xxxxxxxx; ietf@xxxxxxxx; > >>>>>>> draft-ietf-mpls-lsp-ping- > >>>>>>>> relay-reply.all > >>>>>>>> Subject: Re: [mpls] [Gen-art] review: > >>>>>>> draft-ietf-mpls-lsp-ping-relay-reply-04 > >>>>>>>> > >>>>>>>> In line. > >>>>>>>> > >>>>>>>>> On 10/21/14, 10:36 AM, lizho.jin@xxxxxxxxx wrote: > >>>>>>>>> Hi Joel, see inline below, thanks. > >>>>>>>>> > >>>>>>>>> Lizhong > >>>>>>>>> > >>>>>>>>> > >>>>>>>>>> 2014.10.21，PM9:30，Joel M. Halpern <jmh@xxxxxxxxxxxxxxx> > >>>> wrote ： > >>>>>>>>>> > >>>>>>>>>> If the process for this draft is to use the top address that > >>>>>>>>>> can be reached in the routing table, then there is a > >>>>>>>>>> significant probability that the original source address, > >>>>>>>>>> which is always at the top of the list, will be used. As > >>>>>>>>>> such, the intended problem will not be solved. > >>>>>>>>> [Lizhong] let me give an example to explain: the source > >>>>>>>>> address A is firstly added to the stack, then a second > >>>>>>>>> routable address B for replying AS is also added. The reply > >>>>>>>>> node will not use address A since it's not routable, then it > >>>>>>>>> will use address B. So it will work and I don't see the problem. > >>>>>>>> > >>>>>>>> The whole point of this relay mechanism, as I understand it, is > >>>>>>>> to cope > >>>>>>> with > >>>>>>>> the case when the responder X can not actually reach the source > A. > >>>>>>>> Now suppose that the packet arrives at X with the Address > >>>>>>>> stack A, B, > >>>>> ... > >>>>>>> X > >>>>>>>> examines the stack. The domain of A was numbered using net 10. > >>>>>>>> The domain of X is numbered using net 10. A's address is > >>>>>>>> probably > >>>>>>> routable > >>>>>>>> in X's routing table. The problem is, that routing will not > >>>>>>>> get to A. X > >>>>>>> examines > >>>>>>>> the stack, determines that A is "routable", and sends the packet. > >>>>>>>> This > >>>>>>> fails to > >>>>>>>> meet the goal. > >>>>>>> [Lizhong] The source A you are referring is the initiator, right? > >>>>>>> The goal of relay mechanism is to reach the initiator. If X is > >>>>>>> routable to the initiator (address A), then it is great, other > >>>>>>> relay node in the stack will be skipped. > >>>>>>> If the source A you are referring is the interface address of > >>>>>>> one intermediate node, then I do not understand "routing will > >>>>>>> not get to A. X examines the stack, determines that A is > >>>>>>> "routable", and sends the > >>>>>> packet". > >>>>>>> Why routing will not get to A, but A is routable? > >>>>>>> > >>>>>>> Regards > >>>>>>> Lizhong > >>>>>>> > >>>>>>> > >>>>>>>> > >>>>>>>> Yours, > >>>>>>>> Joel > >>>>>>> > >>>>>>> > >>>>>>> > >>>>> > >>> > > > > _______________________________________________ > > mpls mailing list > > mpls@xxxxxxxx > > https://www.ietf.org/mailman/listinfo/mpls