Dino, On Tue, Oct 4, 2016 at 2:24 PM, Dino Farinacci <[email protected]> wrote:
> You said nothing about making a decision. I propose a decision be > announced at Seoul IETF. Which decision are you looking for? Flip a coin & pick one? Picking an encapsulation despite the technical objections on both sides will split the market and affect interoperability. Depending on how much you believe the deployment and key features will be in software or hardware seriously affects the arguments. I have been trying to see if there could be agreement for a design team to get a solution that takes the objections into account and produces something. I have heard from some that they "don't think it is time for a standard and we should just provide high quality documentation"; since standards is what the IETF does, I'm not clear on what the proposed goal would be otherwise. By having a solid and thoughtful conversation about the impact of different encapsulations (and support for different aspects) connected to the many cases in the NVO3 architecture, I am hoping to get a more nuanced and thoughtful understanding of the issues. Regards, Alia > Dino > > > On Oct 4, 2016, at 2:24 AM, Bocci, Matthew (Nokia - GB) < > [email protected]> wrote: > > > > > > Folks, > > > > Following the lengthy discussion on this list about the pros and cons of > the three encapsulation formats, we would like to summarise where the main > points of the discussion and to provide some thoughts on next steps. > > > > As a reminder, the question that we asked was: For a given encap, do you > have significant technical objections? > > > > Thank you for the lively discussion. We have summarised the key points > for each draft as follows: > > > > Geneve > > ---------- > > - Can’t be implemented cost-effectively in all use cases because > variable length header and order of the TLVs makes is costly (in terms of > number of gates) to implement in hardware > > - Fork-lift upgrade from widely deployed VXLAN (no backwards > compatibility mechanisms) > > - Header doesn’t fit into largest commonly available parse buffer (256 > bytes in NIC). Cannot justify doubling buffer size unless it is mandatory > for hardware to process additional option fields. > > > > GUE > > ---------- > > - There were a significant number of objections related to the > complexity of implementation in hardware, similar to those noted for Geneve > above. > > - In addition, there were concerns raised that GUE does not support a > sufficient number of extensions due to its reliance on a limited flags > field, which is already almost 45% allocated. > > > > VXLAN-GPE > > ---------- > > - GPE is not day-1 backwards compatible with VXLAN. Although the frame > format is similar, it uses a different UDP port, so would require changes > to existing implementations even if the rest of the GPE frame is the same. > > - GPE is insufficiently extensible. Numerous extensions and options have > been designed for GUE and Geneve. Note that these have not yet been > validated by the WG. > > - Security e.g. of the VNI has not been addressed by GPE. Although a > shim header could be used for security and other extensions, this has not > been defined yet and its implications on offloading in NICs are not > understood. > > > > Unfortunately, no rough consensus emerged from the list discussion. > > > > The chairs and our AD have also been trying to form a design team to > take forward the encapsulation discussion and see if there is potential to > design a common encapsulation. However, there has been insufficient > interest in this initiative. We would like to hear opinions and > confirmation or disagreement on interest in creating a DP encapsulation > that addresses the various technical concerns. > > > > For the upcoming Seoul IETF, we propose that we will put aside the > discussion of specific encapsulations and focus on control plane and OAM. > In particular, the chairs feel there was insufficient discussion of the > impact of a software solution that implements some or all of the potential > options/extensions allowed by e.g. Geneve on all elements of the NVO3 > architecture. We would like the working group to consider more carefully > the implications of different encapsulations in real environments > consisting of both software and hardware implementations and spanning > multiple data centers. For example, OAM functions such as path MTU > discovery become challenging with multiple encapsulations along the data > path. We would like to encourage solid reviews of the three proposals on > the list, particularly how they would work in the general architecture. > > > > With this in mind, we are also considering holding a virtual interim > meeting the week of 24th October. More details will follow. > > > > We would like to start a conversation within the WG about what > functionality the WG should focus on and standardize. What do you think > should be easy to do? What would be incredibly useful? What, if not done, > risks causing harm to the industry? The start of this discussion of WG > direction will occur on the mailing list and in the virtual interim." > > > > Best regards > > > > Matthew and Sam > > > > > > > > > > > > > > _______________________________________________ > > nvo3 mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/nvo3 > > _______________________________________________ > nvo3 mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/nvo3 >
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