Re: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05
Eric Gray <eric.gray@ericsson.com> Thu, 28 July 2011 17:39 UTC
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From: Eric Gray <eric.gray@ericsson.com>
To: Zhenlong Cui <c-sai@bx.jp.nec.com>, 'Sam Aldrin' <aldrin.ietf@gmail.com>
Date: Thu, 28 Jul 2011 13:39:19 -0400
Thread-Topic: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05
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References: <4DFA60E3.90807@pi.nu><791AD3077F94194BB2BDD13565B6295D13B65A62@Polydeuces.office.hd><C0AC8FAB6849AB4FADACCC70A949E2F10B2256B154@EUSAACMS0701.eamcs.ericsson.se><791AD3077F94194BB2BDD13565B6295D13B69562@Polydeuces.office.hd><C0AC8FAB6849AB4FADACCC70A949E2F10B2484A3ED@EUSAACMS0701.eamcs.ericsson.se><791AD3077F94194BB2BDD13565B6295D13B695EF@Polydeuces.office.hd><D6432A3783F045B694EA0467F7173898@nsl.ad.nec.co.jp><C0AC8FAB6849AB4FADACCC70A949E2F10B24DDE877@EUSAACMS0701.eamcs.ericsson.se><60F069FADFF94B1C8594EEB26514F486@nsl.ad.nec.co.jp><5DA50667-3D9E-4E5F-951A-8125326A3B15@gmail.com><9522723C01DA447B94833A2F6F92B95C@nsl.ad.nec.co.jp><C0AC8FAB6849AB4FADACCC70A949E2F10B24DDEF32@EUSAACMS0701.eamcs.ericsson.se> <662500A437844CE68AC30DB3B9E41C40@nsl.ad.nec.co.jp> <5FF7D74540DE4099930540A97AA013CE@nsl.ad.nec.co.jp>
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Cc: "mpls@ietf.org" <mpls@ietf.org>, "draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org" <draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org>
Subject: Re: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05
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Zhenlong, I'm not sure what you mean by a different behavior between node ID and interface ID. There is certainly a minimum difference associated with what box-local entity it is that is logically responsible for replying to a message. But it seems as if we have converged in this discussion. Thanks for taking the time to review and discuss the draft! -- E -----Original Message----- From: Zhenlong Cui [mailto:c-sai@bx.jp.nec.com] Sent: Thursday, July 28, 2011 1:22 PM To: Eric Gray; 'Sam Aldrin' Cc: mpls@ietf.org; draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org Subject: RE: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05 Importance: High Hi, Eric Small correction to the mail I just sent: ... "protocol redundancy is _not_ what I had in mind when I wrote my original mail." ... Best Zhenlong > -----Original Message----- > From: mpls-bounces@ietf.org [mailto:mpls-bounces@ietf.org] On Behalf Of Zhenlong Cui > Sent: Friday, July 29, 2011 2:04 AM > To: 'Eric Gray'; 'Sam Aldrin' > Cc: mpls@ietf.org; draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org > Subject: Re: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05 > > Hi Eric, > > Sorry, protocol redundancy is what I had in mind when I wrote my original mail. > > I didn't understand why to define a different behavior for "destination node identifier" and "destination interface > identifier". > > In a P2MP scenario, an intermediate node may send multiple responses Which include different return codes (per-interface > MIP case). > > I do understand the draft contains no such requirements for the for P2MP case. > Essentially, the requestor receiving multiple responses which include different return code may not be a problem. > > Lastly, I think this issue might be discussed in the draft-farrel-mpls- tp-mip-mep-map, not here. > > > Thanks for your response. > > > -----Original Message----- > > From: Eric Gray [mailto:eric.gray@ericsson.com] > > Sent: Thursday, July 28, 2011 12:45 AM > > To: Zhenlong Cui; 'Sam Aldrin' > > Cc: mpls@ietf.org; draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org > > Subject: RE: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05 > > > > Not sure why you think the protocol redundancy is necessary, > > or even a good idea. > > > > The DSMAP TLV as defined allows specification of an interface. > > > > Asking for a potentially new TLV that will also provide this > > information in the event that one is unable to handle, read or > > interpret the DSMAP TLV is pointless. If one cannot use one > > TLV, the chances are very good that one cannot use a newer one > > either. > > > > -----Original Message----- > > From: Zhenlong Cui [mailto:c-sai@bx.jp.nec.com] > > Sent: Wednesday, July 27, 2011 10:46 AM > > To: 'Sam Aldrin'; Eric Gray > > Cc: mpls@ietf.org; draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org > > Subject: RE: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05 > > Importance: High > > > > Hi Sam and Eric, > > > > Ok, I understand that the issue of unknown TLVs is outside the scope of this document. > > > > > > Lastly, I suggest that add some mention to this draft regarding responder's behavior for new TLV. > > > > 1) Which return code to send when source/destination identifiersare wrong or drop the request. > > > As said above, it should be dropped, if the source is unknown. > > > > OK, I think this is clear now: > > - A responder will drop requests from an unknown source. > > - A responder will drop requests in case of destination identifier mismatch. (as defined in section 4.2.3.) > > > > > > 2) Which return code to send when ingress if_num/egress if_num of DSMAP TLV are wrong or drop the request. > > > Return code 5, dsmap mismatch. This is already defined in rfc4379. > > > > Regarding the identifiers of nodes and interfaces for route trace which are defined in RFC 5860 as below. > > The information collected MUST include identifiers related to the nodes and interfaces composing that route. > > > > I think "destination node identifier" and "destination interface identifier" are composed for one maintenance entity, > > therefore they > > should have the same behavior in the responder. > > > > So, my suggestions regarding these issues are as follows. > > 1) It should be dropped, if the identifier of the DSMAP TLV is wrong. > > 2) If not, the "interface identifier" should be included in the Destination identifier TLV, or one might define a new TLV. > > > > > > Best, > > Zhenlong > > > > > -----Original Message----- > > > From: Sam Aldrin [mailto:aldrin.ietf@gmail.com] > > > Sent: Wednesday, July 27, 2011 6:29 AM > > > To: Zhenlong Cui > > > Cc: Eric Gray; mpls@ietf.org; draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org > > > Subject: Re: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05 > > > > > > As Eric said in earlier email, these questions are more related to RFC4379 and not just this draft. > > > Having said that, please find responses inline. > > > > > > Sam > > > > > > Sent from my iPad > > > > > > On Jul 26, 2011, at 2:03 PM, "Zhenlong Cui" <c-sai@bx.jp.nec.com> wrote: > > > > > > > Hi Eric, > > > > > > > > I remember you said earlier that you should drop the packet from unknown source nodes, because there is a security > problem > > > with > > > > responding. > > > > On the other hand, you say that you should send a reply when the request includes an unknown TLV. > > > > > > > Unknown source is not same as receiving malformed Tlv or unsupported tlv. > > > > I think if the responder receives a request it checks the type of the TLV before it checks the identifiers. > > > > > > > > So, my question is "if the responder receives a request from an unknown source node that includes an unknown TLV, does > > > the responder > > > > have to reply to the unknown source node?". If yes, this has the security problem you mentioned earlier, doesn't it? > > > If received from unknown source, most vendors drop the packet. > > > > > > > > > > > > Lastly, I suggest that add some mention to this draft regarding responder's behavior for new TLV. > > > > 1) Which return code to send when source/destination identifiers are wrong or drop the request. > > > As said above, it should be dropped, if the source is unknown. > > > > 2) Which return code to send when ingress if_num/egress if_num of DSMAP TLV are wrong or drop the request. > > > Return code 5, dsmap mismatch. This is already defined in rfc4379. > > > > > > > > > > > > Best, > > > > Zhenlong > > > > > > > >> -----Original Message----- > > > >> From: Eric Gray [mailto:eric.gray@ericsson.com] > > > >> Sent: Wednesday, July 27, 2011 12:56 AM > > > >> To: Zhenlong Cui > > > >> Cc: mpls@ietf.org; draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org > > > >> Subject: RE: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05 > > > >> > > > >> Zhenlong, > > > >> > > > >> Q-1: See RFC 4379, where these regitry entries are derived from. > > > >> RFC 4379 sets up a number of registries - including the TLV > > > >> registry - and defines explicitly how to handle unknown TLV > > > >> types in section 3, in two very obscure paragraphs on page > > > >> 10, just before section 3.1. > > > >> > > > >> Q-2: "ingress port" is not correct - thanks for spotting this > > > >> cut-and-paste duplication error. > > > >> > > > >> -- > > > >> Eric > > > >> > > > >> -----Original Message----- > > > >> From: Zhenlong Cui [mailto:c-sai@bx.jp.nec.com] > > > >> Sent: Tuesday, July 12, 2011 5:20 AM > > > >> To: mpls@ietf.org; draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org > > > >> Subject: [mpls] Questions for draft-ietf-mpls-tp-on-demand-cv-05 > > > >> > > > >> Dear Authors, > > > >> > > > >> Two questions regarding the idenfifiers TLV and DSMAP TLV. > > > >> > > > >> Question 1: > > > >>>>> Which return code to send when identifiers are wrong (Malformed echo > > > >>>>> request received?) or drop the packet. > > > >>>>> > > > >>>>> EG > Drop the packet, probably log the error, possibly run off > > > >>>>> EG > screaming into the night. What does one do when one gets > > > >>>>> EG > something either not recognizably intended for one, or not > > > >>>>> EG > from a source that one recognizes? From a security point > > > >>>>> EG > of view, we cannot require an implementation to reply to > > > >>>>> EG > the requester in this case (this is an attack vector for > > > >>>>> EG > all kinds of hate and discontent). Nor can we forbid it. > > > >>>>> > > > >> If the "type" of identifier TLV is incorrect, then should this request frame be dropped? Should we reply to the > requestor(One > > > >> or > > > >> more of the TLVs was not understood)? Can this way two answers be generated? > > > >> > > > >> > > > >> Question 2: > > > >> In section 2.1.1, Is below("ingress port") correct? > > > >> > > > >> Egress IF_Num identifies the ingress port on the target node. A > > > >> value of 0 indicates that the port is not part of the identifier. > > > >> > > > >> > > > >> Best, > > > >> zhenlong > > > >> > > > >>> -----Original Message----- > > > >>> From: mpls-bounces@ietf.org [mailto:mpls-bounces@ietf.org] On Behalf Of Rolf Winter > > > >>> Sent: Monday, June 27, 2011 8:04 PM > > > >>> To: Eric Gray; mpls@ietf.org; draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org > > > >>> Subject: Re: [mpls] Verification call on draft-ietf-mpls-tp-on-demand-cv > > > >>> > > > >>> I think that's OK, since the value is not beyond but within the TLV. Taken from 4379: > > > >>> > > > >>> Types are defined below; Length is the length of the Value field in > > > >>> octets. The Value field depends on the Type; it is zero padded to > > > >>> align to a 4-octet boundary. > > > >>> > > > >>> That means the length is the length of the actual value (excluding the padding). So the beginning of the next TLV > is > > > determined > > > >>> by the length plus a value that makes it align on a 4-octet boundary (which of course can be 0). I cannot follow > your > > > argument > > > >>> why this is not correct. I am sure I am missing something trivial, so sorry for spamming the list. But all information > > > >> is > > > >>> encoded in the packet (plus the simple rule quoted above). Otherwise, a node needs to understand the internal structure > > > >> of > > > >>> each TLV to extract the value instead of applying the simple rule above. > > > >>> > > > >>> > > > >>> Best, > > > >>> > > > >>> Rolf > > > >>> > > > >>> > > > >>> NEC Europe Limited | Registered Office: NEC House, 1 Victoria Road, London W3 6BL | Registered in England 2832014 > > > >>> > > > >>> > > > >>>> -----Original Message----- > > > >>>> From: Eric Gray [mailto:eric.gray@ericsson.com] > > > >>>> Sent: Montag, 27. Juni 2011 12:42 > > > >>>> To: Rolf Winter; mpls@ietf.org; draft-ietf-mpls-tp-on-demand- > > > >>>> cv@tools.ietf.org > > > >>>> Subject: RE: [mpls] Verification call on draft-ietf-mpls-tp-on-demand- > > > >>>> cv > > > >>>> > > > >>>> IMO, that would be a problem with RFC 4379. Perhaps there is > > > >>>> an errata? > > > >>>> > > > >>>> TLVs are meant to follow each other, where the beginning of the > > > >>>> next TLV is determined by the length of the current TLV - hence > > > >>>> it is not correct to specify any content as having any value at > > > >>>> all if it is beyond the end of the TLV. > > > >>>> > > > >>>> -----Original Message----- > > > >>>> From: Rolf Winter [mailto:Rolf.Winter@neclab.eu] > > > >>>> Sent: Monday, June 27, 2011 5:06 AM > > > >>>> To: Eric Gray; mpls@ietf.org; draft-ietf-mpls-tp-on-demand- > > > >>>> cv@tools.ietf.org > > > >>>> Subject: RE: [mpls] Verification call on draft-ietf-mpls-tp-on-demand- > > > >>>> cv > > > >>>> Importance: High > > > >>>> > > > >>>> Hi Eric, > > > >>>> > > > >>>> just one more to follow up. You say: > > > >>>> > > > >>>>> EG > 24 is correct for the Static LSP Sub-TLV (it is 6 words long, > > > >>>>> EG > even if the last two octets "Must be Zero"). The length of > > > >>>>> EG > the Static Pseudowire Sub-TLV - on the other hand - was made > > > >>>>> EG > longer by the addition of the 2-word AGI. Nice catch! > > > >>>> > > > >>>> In RFC 4379, section 3.2, the MUST be Zero parts don't seem to be > > > >>>> included in the length of the sub-TLVs. Why are they included here? > > > >>>> > > > >>>> Best, > > > >>>> > > > >>>> Rolf > > > >>>> > > > >>>> > > > >>>> NEC Europe Limited | Registered Office: NEC House, 1 Victoria Road, > > > >>>> London W3 6BL | Registered in England 2832014 > > > >>>> > > > >>>> > > > >>>>> > > > >>>>> EG > Apparently. > > > >>>>> > > > >>>>> Which return code to send when identifiers are wrong (Malformed echo > > > >>>>> request received?) or drop the packet. > > > >>>>> > > > >>>>> EG > Drop the packet, probably log the error, possibly run off > > > >>>>> EG > screaming into the night. What does one do when one gets > > > >>>>> EG > something either not recognizably intended for one, or not > > > >>>>> EG > from a source that one recognizes? From a security point > > > >>>>> EG > of view, we cannot require an implementation to reply to > > > >>>>> EG > the requester in this case (this is an attack vector for > > > >>>>> EG > all kinds of hate and discontent). Nor can we forbid it. > > > >>>>> > > > >>>>> Using the per-interface model and say the DSMAP TLV did not match the > > > >>>>> ingress IF identifier, then should this request frame be dropped? > > > >>>>> Should we reply to the requestor? Can this way two answers be > > > >>>>> generated? > > > >>>>> > > > >>>>> Nit (section 2.1): s/mpls/MPLS/ > > > >>>>> > > > >>>>> EG > Thanks. > > > >>>>> > > > >>>>> > > > >>>>> Best, > > > >>>>> > > > >>>>> > > > >>>>> > > > >>>>> Rolf > > > >>>>> > > > >>>>> > > > >>>>> > > > >>>>> > > > >>>>> > > > >>>>> > > > >>>>> NEC Europe Limited | Registered Office: NEC House, 1 Victoria Road, > > > >>>>> London W3 6BL | Registered in England 2832014 > > > >>>>> > > > >>>>> > > > >>>>>> -----Original Message----- > > > >>>>>> From: mpls-bounces@ietf.org [mailto:mpls-bounces@ietf.org] On > > > >>>> Behalf > > > >>>>> Of > > > >>>>>> Loa Andersson > > > >>>>>> Sent: Donnerstag, 16. Juni 2011 22:01 > > > >>>>>> To: mpls@ietf.org; draft-ietf-mpls-tp-on-demand-cv@tools.ietf.org; > > > >>>>> Ross > > > >>>>>> Callon; George Swallow; MPLS-TP ad hoc team > > > >>>>>> Subject: [mpls] Verification call on draft-ietf-mpls-tp-on-demand- > > > >>>> cv > > > >>>>>> > > > >>>>>> Working Group. > > > >>>>>> > > > >>>>>> the authors of draft-ietf-mpls-tp-on-demand-cv have updated the ID > > > >>>>>> after wg last call and published version -04 of the document. > > > >>>>>> > > > >>>>>> A document detailing how the comments have been addressed will be > > > >>>>>> found at: > > > >>>>>> http://www.pi.nu/~loa/comments-on-03.xls > > > >>>>>> > > > >>>>>> This is to start a working group call to verify that all comments > > > >>>>>> been adequately addressed. Please send your comments to the > > > >>>>>> mpls working group mailing list before June 24th. > > > >>>>>> > > > >>>>>> Loa > > > >>>>>> on behalf of the MPLS wg co-chairs > > > >>>>>> > > > >>>>>> -- > > > >>>>>> > > > >>>>>> > > > >>>>>> Loa Andersson email: > > > >>>>> loa.andersson@ericsson.com > > > >>>>>> Sr Strategy and Standards Manager loa@pi.nu > > > >>>>>> Ericsson Inc phone: +46 10 717 52 13 > > > >>>>>> +46 767 72 92 13 > > > >>>>>> _______________________________________________ > > > >>>>>> mpls mailing list > > > >>>>>> mpls@ietf.org > > > >>>>>> https://www.ietf.org/mailman/listinfo/mpls > > > >>>>> _______________________________________________ > > > >>>>> mpls mailing list > > > >>>>> mpls@ietf.org > > > >>>>> https://www.ietf.org/mailman/listinfo/mpls > > > >>> _______________________________________________ > > > >>> mpls mailing list > > > >>> mpls@ietf.org > > > >>> https://www.ietf.org/mailman/listinfo/mpls > > > > > > > > > > > > _______________________________________________ > > > > mpls mailing list > > > > mpls@ietf.org > > > > https://www.ietf.org/mailman/listinfo/mpls > > > _______________________________________________ > mpls mailing list > mpls@ietf.org > https://www.ietf.org/mailman/listinfo/mpls
- [mpls] Verification call on draft-ietf-mpls-tp-on… Loa Andersson
- Re: [mpls] Verification call on draft-ietf-mpls-t… binny jeshan
- Re: [mpls] Verification call on draft-ietf-mpls-t… Rolf Winter
- Re: [mpls] Verification call on draft-ietf-mpls-t… Eric Gray
- [mpls] Closing verification call: Re: Verificatio… Loa Andersson
- Re: [mpls] Verification call on draft-ietf-mpls-t… Rolf Winter
- Re: [mpls] Verification call on draft-ietf-mpls-t… Eric Gray
- Re: [mpls] Verification call on draft-ietf-mpls-t… Eric Gray
- Re: [mpls] Verification call on draft-ietf-mpls-t… Rolf Winter
- [mpls] Questions for draft-ietf-mpls-tp-on-demand… Zhenlong Cui
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Eric Gray
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Zhenlong Cui
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Sam Aldrin
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Eric Gray
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Zhenlong Cui
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Eric Gray
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Zhenlong Cui
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Zhenlong Cui
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Eric Gray
- Re: [mpls] Questions for draft-ietf-mpls-tp-on-de… Zhenlong Cui