Hi Greg, I never stated "that mere fact of existing implementation should cancel discussion of technical characteristics of the proposed approaches to hybrid OAM". I just noted implementation status as AN important thing to consider. I also noted that "I've seen several good arguments for why the existing IOAM implementation [...] meets the needs for IOAM." I'm not trying to end discussion of the technical characteristics. I'm stating that I believe that it has been well argued that IOAM is mature enough that it is clear that it is sufficiently different from OOAM as to not share the same header.
I hope that clarifies my intent. Regards, John On Thu, Apr 19, 2018 at 9:30 AM, Greg Mirsky <[email protected]> wrote: > Hi John, > I don't argue with the importance of interoperable implementations (though > early implementations accept the risk of non-compliance with the final > specification, for example, SFC NSH). At the same time, I don't think that > mere fact of existing implementation should cancel discussion of technical > characteristics of the proposed approaches to hybrid OAM. > > Regards, > Greg > > On Thu, Apr 19, 2018 at 9:09 AM, John Lemon <[email protected]> > wrote: > >> I never saw a response to the request for a pointer to an OOAM >> implementation, so I assume none exist. >> >> I've seen several good arguments for why the existing IOAM >> implementation, for which several implementations exist, meets the needs >> for IOAM. >> >> I think it is time to put to bed the request to examine merging OOAM and >> IOAM. Let's move forward with IOAM and not hold it up. >> >> Respectfully, John >> >> >> On Thu, Apr 12, 2018 at 11:06 AM, Frank Brockners (fbrockne) < >> [email protected]> wrote: >> >>> Hi Greg, >>> >>> >>> >>> thanks – and it seems that we’re on the same page with regards to >>> efficiency (4 bytes of non-required overhead) and maturity (or lack of) of >>> OOAM. >>> >>> >>> >>> On the IOAM implementation: There are several implementations of IOAM. >>> Some of which have recently been worked on and shown at an IETF hackathon, >>> see https://datatracker.ietf.org/meeting/100/materials/slides-10 >>> 0-hackathon-sessa-in-situ-oam-ioam - where we’ve shown IPv6 and >>> VXLAN-GPE with IOAM – on FD.io/VPP as well as on Barefoot Tofino. You >>> probably also remember the Netronome/Broadcom demo - >>> https://www.youtube.com/watch?v=j9FbD4a3F4E . >>> >>> Below you seem to be specifically referring to the IOAM open source >>> implementation in FD.io/VPP: There are protocol encapsulations for >>> VXLAN-GPE, NSH, and IPv6 implemented in FD.io/VPP. The current code uses >>> the “next header approach” for VXLAN-GPE and it leverages MD-Type 2 for >>> NSH. As you’re well aware, there the discussion in SFC whether to use >>> MD-Type 2 or next header encapsulating IOAM data in NSH isn’t yet settled, >>> hence we’ll refrain from updating the code until SFC WG has come to a >>> conclusion. >>> >>> >>> >>> Could you provide a pointer to an OOAM implementation? >>> >>> >>> >>> Thanks, >>> >>> Frank >>> >>> >>> >>> *From:* Greg Mirsky <[email protected]> >>> *Sent:* Donnerstag, 12. April 2018 18:54 >>> *To:* Frank Brockners (fbrockne) <[email protected]> >>> *Cc:* IETF IPPM WG <[email protected]>; NVO3 <[email protected]>; Service >>> Function Chaining IETF list <[email protected]>; [email protected] >>> *Subject:* Re: [ippm] encapsulation of IOAM data in various protocols - >>> follow up from WG discussion in London >>> >>> >>> >>> Hi Frank, >>> >>> thank you for sharing your points. Please find my notes in-line and >>> tagged GIM>>. I believe that this is very much relevant to work of other >>> working groups that directly work on the overlay encapsulations in the >>> center of the discussion and hence I've added them to the list. Hope we'll >>> have more opinions to reach the conclusion that is acceptable to all. >>> >>> >>> >>> Regards, >>> >>> Greg >>> >>> >>> >>> On Wed, Apr 11, 2018 at 12:02 PM, Frank Brockners (fbrockne) < >>> [email protected]> wrote: >>> >>> Back at the IPPM meeting in London, we discussed several drafts dealing >>> with the encapsulation of IOAM data in various protocols >>> (draft-brockners-ippm-ioam-vxlan-gpe-00, >>> draft-brockners-ippm-ioam-geneve-00, >>> draft-weis-ippm-ioam-gre-00). One discussion topic that we decided to take >>> to the list was the question on whether draft-ooamdt-rtgwg-ooam-header >>> could be leveraged. After carefully considering >>> draft-ooamdt-rtgwg-ooam-header, I came to the conclusion that the “OOAM >>> header” does not meet the needs of IOAM: >>> >>> * Efficiency: IOAM adds data to live user traffic. As such, an >>> encapsulation needs to be as efficient as possible. The “OOAM header” is 8 >>> bytes long. The approach for IOAM data encapsulation in the above mentioned >>> drafts only requires 4 bytes. Using the OOAM header approach would add an >>> unnecessary overhead of 4 bytes – which is significant. >>> >>> GIM>> The difference in four octets is because OOAM Header: >>> >>> - provides more flexibility, e.g. Flags field and Reserved fields; >>> - supports larger OAM packets than iOAM header; >>> - is future proof by supporting versioning (Version field). >>> >>> * Maturity: IOAM has several implementations, which were also shown at >>> recent IETF hackathons – and we’re expecting additional implementations to >>> be publicized soon. Interoperable implementations need timely >>> specifications. Despite the question being asked, the recent thread on OOAM >>> in the NVO3 list hasn’t revealed any implementation of the OOAM header. In >>> addition, the thread revealed that several fundamental questions about the >>> OOAM header are still open, such as whether or how active OAM mechanisms >>> within protocols such as Geneve would apply to the OOAM header. This >>> ultimately means that we won’t get to a timely specification. >>> >>> GIM>> May I ask which encapsulations supported by the implementations >>> you refer to. Until very recently all iOAM proposals were to use meta-data >>> TLV in, e.g. Geneve and NSH. And if these or some of these implementations >>> already updated to the newly proposed iOAM shim, I don't see problem in >>> making them use OOAM Header. Would you agree? >>> >>> >>> >>> * Scope: It isn’t entirely clear to which protocols the OOAM header >>> would ultimately apply to. The way the OOAM header is defined, OOAM uses a >>> 8-bit field for “Next Prot”, the next protocol. Some protocols that IOAM >>> data needs to be encapsulated into use 16-bits for their next protocol code >>> points. See e.g. the GRE encapsulation – as specified in >>> draft-weis-ippm-ioam-gre-00. >>> >>> GIM>> The first paragraph of the Introduction section states: >>> >>> New protocols that support overlay networks like VxLAN-GPE >>> >>> [I-D.ietf-nvo3-vxlan-gpe], GUE [I-D.ietf-nvo3-gue], Geneve >>> >>> [I-D.ietf-nvo3-geneve], BIER [I-D.ietf-bier-mpls-encapsulation], and >>> >>> NSH [I-D.ietf-sfc-nsh] support multi-protocol payload, e.g. >>> >>> Ethernet, IPv4/IPv6, and recognize Operations, Administration, and >>> >>> Maintenance (OAM) as one of distinct types. That ensures that >>> >>> Overlay OAM (OOAM)packets are sharing fate with Overlay data packet >>> >>> traversing the underlay. >>> >>> I'm updating the OOAM Header draft and along with cleaning nits will >>> update reference to GUE. I think that the list and the statemnt are quite >>> clear in identifying the scope of networks that may benefit from using not >>> only common OOAM Header but common OOAM mechanisms, e.g. Echo >>> Request/Reply >>> <https://tools.ietf.org/html/draft-ooamdt-rtgwg-demand-cc-cv-03>. >>> >>> >>> >>> With the above in mind, I’d suggest that the WG moves forward with >>> specific definitions for encapsulating IOAM data into protocols – per the >>> above mentioned drafts. >>> >>> >>> >>> Regards, Frank >>> >>> >>> _______________________________________________ >>> ippm mailing list >>> [email protected] >>> https://www.ietf.org/mailman/listinfo/ippm >>> >>> >>> >>> _______________________________________________ >>> ippm mailing list >>> [email protected] >>> https://www.ietf.org/mailman/listinfo/ippm >>> >>> >> >
_______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
