Greg, I'm not the expert on ICMP, but as far as I see you are correct.
I very much would like an ICMP expert to look at this, but I don't know who to contact. Can anyone help me? /Loa > Hi Loa, > thank you for bringing to the discussion this liaison. I've looked through > the prescribed processing and I have concerns about the scenario when an > ICMP packet arrives at PE1 with the TTL=3. If I understand the process > correctly, IP TTL is decremented and since it is non-zero, the ICMP packet > is encapsulated in MPLS with MPLS TTL set to 2. If the MPLS network has > more than one P node, that MPLS TTL expires at the second downstream P > node. That node discovers the ICMP packet with TTL=2. And here I see two > cases: > > - IP Dst is unknown to the P node > - IP Dst is, somehow, known to the P node > > In the latter case, the P node will route the ICMP packet. In the former, > as I understand it, will drop its ICMP Host unreachable. Either case is > troublesome. > Am I missing something in the process described in the liaison? Do you see > a mistake in my thinking? > > Regards, > Greg > > On Fri, Feb 16, 2024 at 2:08â¯AM <l...@pi.nu> wrote: > >> All, >> >> We have the liaison: >> >> "LS on the consent of draft Recommendation ITU-T Q.3962 (ex. Q.joint_tr) >> Requirements and Reference Model for optimized traceroute of joint >> Internet Protocol/Multi-Protocol Label Switching". >> >> I have tried to read the Recommendation, still have some concerns and >> questions. >> >> The liaison was addressed to the OPSAWG, but Tianran (OPSAWG co-chair) >> sent this to the MPLS WG that seem better fitted to respond if we want >> to. >> >> One questions for the OPSAWG is that if the MPLS WG decides to respond >> would the OPSAWG want to join in on the response? >> >> My concerns at moment are (possible there will be more) are rather high >> level. >> >> The consented document is about "IP/MPLS" traceroute. This is core >> IETF/IP >> areas, and within the IETF design authority.. If the intention is to >> align SG-11 protocols with IETF technology that is OK. >> >> If it is it is a bit odd that neither STD5 (which include ICMP) nor >> RFC >> 8029 are mentioned. In fact a consented Recommendation on IETF core >> technology does not mention a single RFC. >> >> If the intention is to create an ITU-T owned version of traceroute we >> are >> back in the discussion on honoring design authorities. >> >> The terminology is not well aligned with the IETF RFC. There are >> "MultiProtocol Label Switch" rather than "MultiProtocol Label >> Switching", >> MPLS tags (sic!), CE is said to be expanded as "Customer Equipment", >> while >> the common IETF usage is "Customer Edge", and there is more. >> >> Figure 6-1 deserves some scrutiny >> >> - the PEs seem to belong to both carrier and enterprise network >> - half of the CE seem to belong to the enterprise network and the >> other half to something undefined. >> >> Also figure 6-1, a normal MPLS network deployment would have IP >> connectivity end to end and traceroute would just work over IP. >> >> Havin said that there is not always IP, e.g. MPLS-TP is built on the >> assumption. that IP connectivity is not necessary. >> >> >> I think we have good reason to respond even though the Liaison is "For >> Information". >> >> I don't know where the responsibility for STD5/ICMP lies, but possibly >> someone that know could forward. >> >> And I think it would be a good idea to call on Scott to coordinate a >> response. >> >> /Loa >> >> >> > <html><head><meta http-equiv="content-type" content="text/html; >> > charset=utf-8"></head><body dir="auto"><br >> > id="lineBreakAtBeginningOfSignature"><div dir="ltr">Sent from my >> iPhone</div><div dir="ltr"><br>Begin forwarded >> > message:<br><br></div><blockquote type="cite"><div >> dir="ltr"><b>From:</b> >> > Greg Mirsky <gregimir...@gmail.com><br><b>Date:</b> 29 October >> 2023 >> > at 04:21:17 GMT+8<br><b>To:</b> Tony Li >> > <tony...@tony.li><br><b>Cc:</b> m...@ietf.org, Henk Birkholz >> <henk.birkh...@sit.fraunhofer.de>, liaison-coordinat...@iab.org, >> Tianran Zhou <zhoutianran=40huawei....@dmarc.ietf.org>, Warren >> Kumari <war...@kumari.net>, Joe Clarke <jcla...@cisco.com>, >> mpls-cha...@ietf.org, Robert Wilton <rwil...@cisco.com>, >> > itu-t-liai...@iab.org, rtg-...@ietf.org<br><b>Subject:</b> <b>Re: >> [mpls] >> New Liaison Statement, "LS on the consent of draft Recommendation ITU-T >> Q.3962 (ex. Q.joint_tr) âRequirements and Reference Model for >> optimized >> > traceroute of joint Internet Protocol/Multi-Protocol Label >> > Switchingâ"</b><br><br></div></blockquote><blockquote >> type="cite"><div >> dir="ltr"><div dir="ltr">Hi Tony,<div>it appears to me that what this >> recommendations describes is Uniform tunneling model (<a >> > href="https://datatracker.ietf.org/doc/html/rfc3443";>RFC 3443</a>) for >> treating ICMP over MPLS (not sure whether the proponents of the >> recommendation argue for using the uniform model for subscriber traffic >> in >> > >> general).</div><div><br></div><div>Regards,</div><div>Greg</div></div><br><div >> class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Oct 28, >> 2023 >> > at 10:35â¯AM Tony Li <<a >> > href="mailto:tony...@tony.li";>tony...@tony.li</a>> >> > wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px >> 0px >> > 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br> >> Perhaps a pointer to IOAM-DEX and a âthanks, already doneâ?<br> <br> >> > T<br> >> > <br> >> > <br> >> > > On Oct 28, 2023, at 10:14â¯AM, Adrian Farrel <<a >> > href="mailto:adr...@olddog.co.uk"; >> > target="_blank">adr...@olddog.co.uk</a>> wrote:<br> >> > > <br> >> > > Thanks Tianran,<br> >> > > <br> >> > > I think you're right that these requirements are something the >> MPLS >> working group may want to look at.<br> >> > > <br> >> > > Working group: unless you have ITU-T internal access, look at the >> copy of Q.3982 that was attached and can be seen at <a >> > href=" >> https://www.ietf.org/lib/dt/documents/LIAISON/liaison-2023-10-24-itu-t-sg-11-opsawg-ls-on-the-consent-of-draft-recommendation-itu-t-q3962-ex-qjoint_tr-requirements-and-reference-model-for-optim-attachment-1.pdf >> " >> rel="noreferrer" >> > target="_blank"> >> https://www.ietf.org/lib/dt/documents/LIAISON/liaison-2023-10-24-itu-t-sg-11-opsawg-ls-on-the-consent-of-draft-recommendation-itu-t-q3962-ex-qjoint_tr-requirements-and-reference-model-for-optim-attachment-1.pdf >> </a> >> Don't follow the URL in the liaison statement.<br> >> > > <br> >> > > The liaison is "for information", but we might want to look to >> see >> whether there is anything we can learn from the requirements presented, >> whether we think there are existing ways of solving the problem >> presented, >> > and whether there is any response we want to send.<br> >> > > <br> >> > > Thanks,<br> >> > > Adrian<br> >> > > <br> >> > > -----Original Message-----<br> >> > > From: mpls <<a href="mailto:mpls-boun...@ietf.org"; >> > target="_blank">mpls-boun...@ietf.org</a>> On Behalf Of Tianran >> Zhou<br> >> > > Sent: 28 October 2023 10:10<br> >> > > To: Liaison Statement Management Tool <<a >> > href="mailto:stateme...@ietf.org"; >> > target="_blank">stateme...@ietf.org</a>>; Henk Birkholz <<a >> href="mailto:henk.birkh...@sit.fraunhofer.de"; >> > target="_blank">henk.birkh...@sit.fraunhofer.de</a>>; Joe Clarke >> <<a >> > href="mailto:jcla...@cisco.com"; >> target="_blank">jcla...@cisco.com</a>>; >> > <a href="mailto:m...@ietf.org"; target="_blank">m...@ietf.org</a>; <a >> href="mailto:mpls-cha...@ietf.org"; >> > target="_blank">mpls-cha...@ietf.org</a><br> >> > > Cc: Tatiana Kurakova <<a >> href="mailto:tatiana.kurak...@itu.int"; >> target="_blank">tatiana.kurak...@itu.int</a>>; Henk Birkholz <<a >> href="mailto:henk.birkh...@sit.fraunhofer.de"; >> > target="_blank">henk.birkh...@sit.fraunhofer.de</a>>; <a >> > href="mailto:liaison-coordinat...@iab.org"; >> > target="_blank">liaison-coordinat...@iab.org</a>; Robert Wilton <<a >> href="mailto:rwil...@cisco.com"; >> target="_blank">rwil...@cisco.com</a>>; >> > <a href="mailto:itu-t-liai...@iab.org"; >> > target="_blank">itu-t-liai...@iab.org</a>; Joe Clarke <<a >> > href="mailto:jcla...@cisco.com"; >> target="_blank">jcla...@cisco.com</a>>; >> > Operations and Management Area Working Group Discussion List <<a >> href="mailto:opsawg@ietf.org"; target="_blank">opsawg@ietf.org</a>>; >> Warren Kumari <<a href="mailto:war...@kumari.net"; >> > target="_blank">war...@kumari.net</a>><br> >> > > Subject: Re: [mpls] New Liaison Statement, "LS on the consent of >> draft Recommendation ITU-T Q.3962 (ex. Q.joint_tr) âRequirements and >> Reference Model for optimized traceroute of joint Internet >> > Protocol/Multi-Protocol Label Switchingâ"<br> >> > > <br> >> > > Hi MPLS WG,<br> >> > > <br> >> > > I forward this LS to MPLS because I believe it not really belongs >> to >> > OPSAWG.<br> >> > > I think MPLS WG should be the right place to receive.<br> >> > > <br> >> > > Best,<br> >> > > Tianran<br> >> > > <br> >> > > <br> >> > > -----Original Message-----<br> >> > > From: Liaison Statement Management Tool [mailto:<a >> > href="mailto:stateme...@ietf.org"; >> target="_blank">stateme...@ietf.org</a>] >> > <br> >> > > Sent: Tuesday, October 24, 2023 11:23 PM<br> >> > > To: Henk Birkholz <<a >> > href="mailto:henk.birkh...@sit.fraunhofer.de"; >> > target="_blank">henk.birkh...@sit.fraunhofer.de</a>>; Joe Clarke >> <<a >> > href="mailto:jcla...@cisco.com"; >> target="_blank">jcla...@cisco.com</a>>; >> > Tianran Zhou <<a href="mailto:zhoutian...@huawei.com"; >> > target="_blank">zhoutian...@huawei.com</a>><br> >> > > Cc: Henk Birkholz <<a >> > href="mailto:henk.birkh...@sit.fraunhofer.de"; >> > target="_blank">henk.birkh...@sit.fraunhofer.de</a>>; Joe Clarke >> <<a >> > href="mailto:jcla...@cisco.com"; >> target="_blank">jcla...@cisco.com</a>>; >> > Operations and Management Area Working Group Discussion List <<a >> href="mailto:opsawg@ietf.org"; target="_blank">opsawg@ietf.org</a>>; >> Robert Wilton <<a href="mailto:rwil...@cisco.com"; >> > target="_blank">rwil...@cisco.com</a>>; Scott Mansfield >> > <scott.mansfi...@ericsson.com>; Tatiana Kurakova <<a >> > href="mailto:tatiana.kurak...@itu.int"; >> > target="_blank">tatiana.kurak...@itu.int</a>>; Tianran Zhou <<a >> href="mailto:zhoutian...@huawei.com"; >> > target="_blank">zhoutian...@huawei.com</a>>; Warren Kumari <<a >> href="mailto:war...@kumari.net"; >> target="_blank">war...@kumari.net</a>>; >> > <a href="mailto:itu-t-liai...@iab.org"; >> > target="_blank">itu-t-liai...@iab.org</a>; <a >> > href="mailto:liaison-coordinat...@iab.org"; >> > target="_blank">liaison-coordinat...@iab.org</a><br> >> > > Subject: New Liaison Statement, "LS on the consent of draft >> Recommendation ITU-T Q.3962 (ex. Q.joint_tr) âRequirements and >> Reference >> > Model for optimized traceroute of joint Internet >> Protocol/Multi-Protocol >> Label Switchingâ"<br> >> > > <br> >> > > Title: LS on the consent of draft Recommendation ITU-T Q.3962 >> (ex. >> Q.joint_tr) âRequirements and Reference Model for optimized traceroute >> of joint Internet Protocol/Multi-Protocol Label Switchingâ<br> > >> Submission Date: 2023-10-24<br> >> > > URL of the IETF Web page: <a >> > href="https://datatracker.ietf.org/liaison/1869/"; rel="noreferrer" >> target="_blank">https://datatracker.ietf.org/liaison/1869/</a><br> > >> <br> >> > > From: Denis ANDREEV <<a href="mailto:tsbs...@itu.int"; >> > target="_blank">tsbs...@itu.int</a>><br> >> > > To: Henk Birkholz <<a >> > href="mailto:henk.birkh...@sit.fraunhofer.de"; >> > target="_blank">henk.birkh...@sit.fraunhofer.de</a>>,Joe Clarke >> <<a >> > href="mailto:jcla...@cisco.com"; >> > target="_blank">jcla...@cisco.com</a>>,Tianran Zhou <<a >> > href="mailto:zhoutian...@huawei.com"; >> > target="_blank">zhoutian...@huawei.com</a>><br> >> > > Cc: Robert Wilton <<a href="mailto:rwil...@cisco.com"; >> > target="_blank">rwil...@cisco.com</a>>,Warren Kumari <<a >> > href="mailto:war...@kumari.net"; >> > target="_blank">war...@kumari.net</a>>,<a >> > href="mailto:itu-t-liai...@iab.org"; >> > target="_blank">itu-t-liai...@iab.org</a> <<a >> > href="mailto:itu-t-liai...@iab.org"; >> > target="_blank">itu-t-liai...@iab.org</a>>,Joe Clarke <<a >> > href="mailto:jcla...@cisco.com"; >> > target="_blank">jcla...@cisco.com</a>>,Scott Mansfield >> > <scott.mansfi...@ericsson.com>,Operations and Management Area >> Working Group Discussion List <<a href="mailto:opsawg@ietf.org"; >> target="_blank">opsawg@ietf.org</a>>,Henk Birkholz <<a >> > href="mailto:henk.birkh...@sit.fraunhofer.de"; >> > target="_blank">henk.birkh...@sit.fraunhofer.de</a>>,Tianran Zhou >> <<a href="mailto:zhoutian...@huawei.com"; >> > target="_blank">zhoutian...@huawei.com</a>> Response Contacts: >> Tatiana >> > Kurakova <<a href="mailto:tatiana.kurak...@itu.int"; >> > target="_blank">tatiana.kurak...@itu.int</a>> Technical Contacts: >> <br> >> > > Purpose: For information<br> >> > > <br> >> > > Body: This liaison statement provides information about the >> consented >> > item as a result of the ITU-T SG11 meeting (Geneva, 10-20 October >> 2023).<br> >> > > <br> >> > > ITU-T SG11 would like to inform ITU-T Study Group 13 and IETF >> about >> the draft new Recommendation ITU-T Q.3962 (ex. Q. joint_tr) >> > âRequirements and Reference Model for optimized traceroute of joint >> Internet Protocol/Multi-Protocol Label Switchingâ which was consented >> during the ITU-T SG11 meeting (Geneva, 10-20 October 2023).<br> >> > > <br> >> > > The draft new Recommendation ITU-T Q. 3962 (ex. Q. joint_tr) >> âRequirements and Reference Model for optimized traceroute of joint >> Internet Protocol/Multi-Protocol Label Switchingâ is attached for your >> convenience.<br> >> > > ITU-T SG11 looks forward to collaborating with ITU-T Study Group >> 13 >> and IETF on this matter.<br> >> > > <br> >> > > Attachment:<br> >> > > SG11-TD747/GEN: Consent â draft Recommendation ITU-T Q.3962 >> (ex. >> Q.joint_tr): Requirements and Reference Model for optimized traceroute >> of >> > joint Internet Protocol/Multi-Protocol Label Switching (Geneva, 10-20 >> October 2023)<br> >> > > Attachments:<br> >> > > <br> >> > > SG11-LS108-Att-TD747<br> >> > > <a >> > href=" >> https://www.ietf.org/lib/dt/documents/LIAISON/liaison-2023-10-24-itu-t-sg-11-opsawg-ls-on-the-consent-of-draft-recommendation-itu-t-q3962-ex-qjoint_tr-requirements-and-reference-model-for-optim-attachment-1.pdf >> " >> rel="noreferrer" >> > target="_blank"> >> https://www.ietf.org/lib/dt/documents/LIAISON/liaison-2023-10-24-itu-t-sg-11-opsawg-ls-on-the-consent-of-draft-recommendation-itu-t-q3962-ex-qjoint_tr-requirements-and-reference-model-for-optim-attachment-1.pdf >> </a><br> >> > <br> >> > > SG11-LS108<br> >> > > <a >> > href=" >> https://www.ietf.org/lib/dt/documents/LIAISON/liaison-2023-10-24-itu-t-sg-11-opsawg-ls-on-the-consent-of-draft-recommendation-itu-t-q3962-ex-qjoint_tr-requirements-and-reference-model-for-optim-attachment-2.docx >> " >> rel="noreferrer" >> > target="_blank"> >> https://www.ietf.org/lib/dt/documents/LIAISON/liaison-2023-10-24-itu-t-sg-11-opsawg-ls-on-the-consent-of-draft-recommendation-itu-t-q3962-ex-qjoint_tr-requirements-and-reference-model-for-optim-attachment-2.docx >> </a><br> >> > <br> >> > > <br> >> > > <br> >> > > _______________________________________________<br> >> > > mpls mailing list<br> >> > > <a href="mailto:m...@ietf.org"; >> target="_blank">m...@ietf.org</a><br> >> > > <a href="https://www.ietf.org/mailman/listinfo/mpls"; >> rel="noreferrer" >> > target="_blank">https://www.ietf.org/mailman/listinfo/mpls</a><br> >> > >> <br> >> > > _______________________________________________<br> >> > > mpls mailing list<br> >> > > <a href="mailto:m...@ietf.org"; >> target="_blank">m...@ietf.org</a><br> >> > > <a href="https://www.ietf.org/mailman/listinfo/mpls"; >> rel="noreferrer" >> > target="_blank">https://www.ietf.org/mailman/listinfo/mpls</a><br> >> <br> >> _______________________________________________<br> >> > mpls mailing list<br> >> > <a href="mailto:m...@ietf.org"; target="_blank">m...@ietf.org</a><br> >> <a >> href="https://www.ietf.org/mailman/listinfo/mpls"; rel="noreferrer" >> target="_blank">https://www.ietf.org/mailman/listinfo/mpls</a><br> >> </blockquote></div> >> > >> <span>_______________________________________________</span><br><span>mpls >> mailing >> > list</span><br><span>m...@ietf.org</span><br><span> >> https://www.ietf.org/mailman/listinfo/mpls >> </span><br></div></blockquote></body></html> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> > _______________________________________________ OPSAWG mailing list OPSAWG@ietf.org https://www.ietf.org/mailman/listinfo/opsawg
