Babel WG VIRTUAL - Tuesday, 26 July 2021 21:30-22:30 (UTC) Room 4 14:30-15:30 (OS Pacific Time) Chairs: Russ White (Juniper) Donald Eastlake (Futurewei) Area Director: Martin Vigoureux (Nokia) Minutes: Taken by Barbara Stark, edited by Donald Eastlake Agenda (amount of time originally scheduled, not time taken) 3 min. Administrativia (scribes), Agenda Bashing, Chairs 7 min. Status, Milestones, Chairs draft-ietf-babel-yang-model-10 15 min. Let’s revive Babel-RTT, Juliusz Chroboczek draft-ietf-babel-rtt-extension-00 25 min. Wi-Fi Addressing, Transit, Multicast, Mesh, Donald Eastlake 3 min. Wrap-Up, Chairs Barbara Stark volunteered to take minutes. A youtube video of the seesion is at https://www.youtube.com/watch?v=uM1McPr4oK8 Administrivia, Status, Milestones ================================= Chair Slides: Donald Eastlake (Futurewei, Chair): Donald went through the chair slides. On slide covered draft-ietf-yang-model. Mahesh Jethanandani (Kloud Services): Mahesh spoke to the slide on the YANG model. It is almost done with IESG review. One last set of comments from Ben will be addressed after this IETF meeting and a revised draft uploaded. Donald: Despite by best efforts to add some not-yet-accomplished future milestones, the working group was only agreeable to adding one and we have done that so it is still true that we have accomplished all our milestones. Let’s Revive Babel-RT ===================== Slides Juliusz Chroboczek (IRIF, University of Paris) presented. After the slides he asked for comments/suggestions: Donald: I think you should use different type values for the sub-TLVs, as you suggest. And that experimental is a good category. Juliusz: There is some argument for keeping it compatible with the current implemented base. There is less liberty to the implementor to do the wrong thing. There are good reasons to use the same TLVs and good reasons not to. Donald: Compatibility with running code is a strong argument. David Schinazi (Google, jabber): Since both current or new sub-TLVs work, I would suggest keeping what is in production today Donald: There has been considerable interest in this in the WG, both in meetings and on the mailing list, so it seems like a good idea to continue work on it. Wi-Fi Addressing, Transit, Multicast, Mesh ========================================== Slides Donald Eastlake presented. Juliusz: Going back to slide 12. Why are there up to 4 addresses instead of just 2? Donald: One set is link local, the other in "end-to-end". You normally have 4 addresses, it is just that usually you have two Layer 3 addresses and two Layer 2 addresses. So the addresses just aren’t of the same kind. Since 802.11 is from the IEEE 802 world, it only uses MAC addresses. The "Distribution System" show on slide 6 does routing but is deliberately underspecified in the 802.11 standard. You can implement the Distribution System routing however you want, with Layer 2 or Layer 3 mechanisms, because standard doesn’t specify. Juliusz: Radia Perlman has a beautiful talk that says "~routing should be done at Layer 3 but people want to do it at Layer 2 so I designed TRILL as a way that they can at least do Layer 2 routing properly~". Why not do routing at Layer 3 where it belongs? Donald: TRILL is really more like Layer 3 routing (IS-IS) but using flat MAC addresses rather than hierarchically structured IP addresses. Juliusz: If a DS routes at Layer 2, it will cause a lot of extra complexity. Why do people want to rqoute at Layer 2? Layer 2 is unnecessarily complicated. I think there are two reasons. Layer 3 configuration is harder. The other reason is it also allows for easier mobility to do routing at L2. Donald: The 5G core is also an example of L2 routing. Juliusz: My hypothesis is that you have 4 addresses because you’re doing routing. It should be possible to do the DS at Layer 3, similarly to what the LTE core network does. I would like to point people to git clone https://www.irif.fr/~jch/software/sroamd.git . I hope to get back to this. Closing ======= Donald: We’re out of time. See you at the next meeting and on the mailing list. If there is enough interest in a topic, we can schedule an interim meeting to make more rapid progress.