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> 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, when the 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> > *Sent:* Monday, November 8, 2021 2:57 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 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> 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> > *Sent:* Sunday, November 7, 2021 9:01 PM > *To:* draft-fz-spring-srv6-alt-m...@ietf.org; spring@ietf.org; > 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 >
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