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 2:08 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) “Requirements and Reference Model for > optimized > > traceroute of joint Internet Protocol/Multi-Protocol Label > > Switching”"</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 10:35 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 “thanks, already done”?<br> <br> > > T<br> > > <br> > > <br> > > > On Oct 28, 2023, at 10:14 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) “Requirements and > Reference Model for optimized traceroute of joint Internet > > Protocol/Multi-Protocol Label Switching”"<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) “Requirements and > Reference > > Model for optimized traceroute of joint Internet Protocol/Multi-Protocol > Label Switching”"<br> > > > <br> > > > Title: 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”<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) > > “Requirements and Reference Model for optimized traceroute of joint > Internet Protocol/Multi-Protocol Label Switching” 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) > “Requirements and Reference Model for optimized traceroute of joint > Internet Protocol/Multi-Protocol Label Switching” 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 – 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> > > > > > > > > > > > > > > >
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