On Tue, Nov 9, 2021 at 7:31 AM Joel M. Halpern <j...@joelhalpern.com> wrote: > > Let me try phrasing the question about the SRH TLV in a different way. > And this is as a participant, not as co-chair. > Assumptions as I understand them: > > 1) The 6man draft requires support of both the HbH and DoH cases > 2) Any node supporting the SRH altMarking can be assumed to also support > the 6man altMark > > If assumption 2 is accurate, then it seems to me that adding the SRH TLV > adds complexity to save a few bits without adding any capability. > This strikes me as a bad trade.
+1 Also, destination and hop-by-hop options have the advantage that they work with any other extension header or protocol. SRH TLVs only work in the narrow use case of SRv6 and don't help router headers that might be defined. Tom > > Yours, > Joel > > On 11/8/2021 2:28 PM, Giuseppe Fioccola wrote: > > Hi Greg, > > > > Yes, with DOH + SRH, the end node of a segment should still conform to > > RFC8200, based on the discussion in 6MAN. > > > > The proposal to use HBH is also mentioned in draft-ietf-6man-ipv6-alt-mark. > > > > Regards, > > > > Giuseppe > > > > *From:* Greg Mirsky <gregimir...@gmail.com> > > *Sent:* Monday, November 8, 2021 6:17 PM > > *To:* Giuseppe Fioccola <giuseppe.fiocc...@huawei.com> > > *Cc:* draft-fz-spring-srv6-alt-m...@ietf.org; spring@ietf.org; i...@ietf.org > > *Subject:* Re: A question for draft-fz-spring-srv6-alt-mark > > > > Hi Giuseppe, > > > > thank you for the clarification. > > > > I was considering the DOH+SDH but am not sure if the end node of a > > segment conforms to the note attributed to DOH in RFC 8200: > > > > note 3: for options to be processed only by the final destination of > > the packet. > > > > I recall the discussion in 6man WG but not the final conclusion of it. > > > > My proposal to use HbH EH included the use of the management plane to > > explicitly enable AltMarking only on segment end-points and keep it > > disabled on transit nodes. > > > > Regards, > > > > Greg > > > > On Mon, Nov 8, 2021 at 8:50 AM Giuseppe Fioccola > > <giuseppe.fiocc...@huawei.com <mailto:giuseppe.fiocc...@huawei.com>> wrote: > > > > Hi Greg, > > > > The use of HbH EH does not fit well in the case of SRH. Indeed, with > > the AltMark HbH Option, it is possible to monitor every router on > > the path with feature enabled, so it potentially allows the > > measurement to every nodes in the path and not only to the nodes > > that are identities in the SR path. > > > > While, with the Destination Option preceding a Routing Header, it is > > possible to apply the measurement to every destination node in the > > route list. This means that, whenthe AltMark Destination Option > > precedes the SRH, it allows the measurement for all the nodes that > > are identities in the SR path. > > > > The solution with SRH TLV is equivalent to DOH + SRH, but it can be > > an optimized solution for SRH since it leverages the SRH TLV > > capability, without adding an additional EH that can be a problem in > > some cases. > > > > Regards, > > > > Giuseppe > > > > *From:* Greg Mirsky <gregimir...@gmail.com > > <mailto:gregimir...@gmail.com>> > > *Sent:* Monday, November 8, 2021 2:57 PM > > *To:* Giuseppe Fioccola <giuseppe.fiocc...@huawei.com > > <mailto:giuseppe.fiocc...@huawei.com>> > > *Cc:* draft-fz-spring-srv6-alt-m...@ietf.org > > <mailto:draft-fz-spring-srv6-alt-m...@ietf.org>; spring@ietf.org > > <mailto:spring@ietf.org>; i...@ietf.org <mailto:i...@ietf.org> > > *Subject:* Re: A question for draft-fz-spring-srv6-alt-mark > > > > Hi Giuseppe, > > > > thank you for the detailed explanation of what the authors consider > > as the problem. In the presentation, you've mentioned that the new > > AltMark SRH TLV allows for better control of which nodes along an SR > > Policy participate in the measurement. I imagine that the HbH IPv6 > > extension header that includes the AltMark TLV can be used to > > achieve the same result if only SR nodes are enabled for the AltMark > > processing. What do you think of using the HbH EH? Am I missing > > something? > > > > Regards, > > > > Greg > > > > On Mon, Nov 8, 2021 at 1:13 AM Giuseppe Fioccola > > <giuseppe.fiocc...@huawei.com <mailto:giuseppe.fiocc...@huawei.com>> > > wrote: > > > > Hi Greg, > > > > Thank you for your comment. > > > > It is very good to have your support on this draft. > > > > draft-ietf-6man-ipv6-alt-mark defines the AltMark DOH. In case of > > SRH, DOH + SRH can be used to implement the measurement for every > > node that is an identity in the SR path. > > > > But, the approach with DOH + SRH requires two extension headers and > > this can have operational implications. > > > > The goal of this draft is to find an optimized solution that best > > suits for SRH. Therefore we propose to use the SRH TLV. If accepted, > > this document would update draft-ietf-6man-ipv6-alt-mark only for SRv6: > > > > - in case of SRH there would be a single way to apply AltMark > > through SRH TLV, > > > > - while for all the other cases with IPv6 data plane the use of the > > HbH and DOH is the only choice to carry AltMark data fields. > > > > Regards, > > > > Giuseppe > > > > *From:* Greg Mirsky <gregimir...@gmail.com > > <mailto:gregimir...@gmail.com>> > > *Sent:* Sunday, November 7, 2021 9:01 PM > > *To:* draft-fz-spring-srv6-alt-m...@ietf.org > > <mailto:draft-fz-spring-srv6-alt-m...@ietf.org>; spring@ietf.org > > <mailto:spring@ietf.org>; i...@ietf.org <mailto:i...@ietf.org> > > *Subject:* A question for draft-fz-spring-srv6-alt-mark > > > > Dear Authors et al. > > > > thank you for this document. I am supporting and following the work > > on the Alternate Marking method in various IETF WGs. What do you see > > as the benefits of defining a new SRH TLV for the Alternate Marking > > method compared to solutions defined for IPv6 in > > draft-ietf-6man-ipv6-alt-mark > > <https://datatracker.ietf.org/doc/draft-ietf-6man-ipv6-alt-mark/>? > > > > Regards, > > > > Greg > > > > > > -------------------------------------------------------------------- > > IETF IPv6 working group mailing list > > i...@ietf.org > > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > > -------------------------------------------------------------------- > > > > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > i...@ietf.org > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- _______________________________________________ spring mailing list spring@ietf.org https://www.ietf.org/mailman/listinfo/spring
