BABEL Working Group Hilton Prague, Prague, Czech Republic. Monday, 17 July 2017. 17:40 - 18:40 Athens/Barcelona Room Chairs: Russ White (LinkedIn) Donald Eastlake (Huawei) Minutes: Barbara Stark, Russ White Jabber: Michael Richardson Note well was noted. Chair slides presented: https://www.ietf.org/proceedings/99/slides/slides-99-babel-agenda-and-status-01.pdf Agenda - 4 min. Administrativia (scribes), Agenda Bashing, Chairs - 4 min. Status, Review of Milestones, Chairs - 12 min. Mandatory sub-TLVs in Babel, Juliusz Chroboczek draft-ietf-babel-rfc6126bis - 10 min. Unicast Hellos, David Schinazi - 5 min. Information Model, Barbara H. Stark draft-ietf-babel-information-model - 10 min. BIER in Babel, Zheng Zhang draft-zhang-bier-babel-extensions-01 - 10 min. Source-Specific Routing for Babel, Matthieu Boutier draft-boutier-babel-source-specific-02 - 4 min. Wrap-Up, Chairs Current draft discussions Applicability draft was declared to have NOT passed WGLC. It will be updated and pushed through last call again ----------- Mandatory sub-TLVs in Babel, Juliusz Chroboczek Juliusz Chroboczek presented: https://www.ietf.org/proceedings/99/slides/slides-99-babel-mandatory-sub-tlvs-in-babel-00.pdf - slide 3: David Schinazi: We have 2 implementations of unicast hellos (joking: "1.5 implementations"). Toke and I intend to try to test interoperability this week. - slide 10: Tony Przygienda: You could stick a capabilties TLV that is advertised per router -- and those that don't have the capability can be ignored/ignore the extensions This is difficult with a distance vector protocol, because the capability is not carried throughout the entire network (as in link state) - Slide 11: David: Really dislikes option of bumping protocol version. Disagree with need for flag day. You can just do both and upgrade routers over time. On slide 10, comparing the 2 options. Bump the protocol is messy. Juliusz: It's simpler than you make it. You can always send 2 unless you set the mandatory bit, then you send 3. David: But if I send some packets with v2 and some with v3, I think you end up breaking principals of loop avoidance. Juliusz: No you can create black holes. David: Are black holes ok? Margaret Cullen: Are you confident the implementations we have will ignore the additional bit? Juliusz: Yes Michael Richardson: I'm not thrilled about v2 to v3. What happens when we go to v4? We still maintain v2? It seems better to remember what talks v2 or v3 and send appropriate packets. Toke Høiland-Jørgensen: I'm not sure it solves the problem when you have half a network. Not sure the complexity is worth it. ----------- Unicast Hellos, David Schinazi Presented slides: https://www.ietf.org/proceedings/99/slides/slides-99-babel-unicast-hellos-00.pdf Slide 7: Juliusz: That's not part of the doc and should not be used for neighbor acquisition. David: Doc currently says if you only see scheduled hellos . And this says... John Dowdell: If you receive multicast and respond unicast, does that mean everything from thereafter is unicast? David: In Babel, you keep sending hellos periodically, and you reply with IHUs. So if you keep seeing hellos and IHUs from your neighbors, you know they're still there. It's a periodic thing. Juliusz: 2 comments. One is you are allowed to send "multicast" hellos over unicast. A hello must be sent to all neighbors. Nothing breaks if you send to all neighbors over unicast. So new doc version says must send hellos either to all via unicast, or with multicast. Is it worth the complexity? 2nd comment is we are contradicting ourselves. Must parse unicast hello and can drop after parsing it. Russ: I'd like to take further discussion but not now because I also have unicast questions. David: There is ambiguity of sending unicast to all being like multicast. ----- Information Model, Barbara H. Stark Presented slides: https://www.ietf.org/proceedings/99/slides/slides-99-babel-babel-information-model-00.pdf Slide 3: Juliusz: In second point, the parameters should be removed. Barbara: They have been removed, but there was question as to whether to add them per interface Juliusz: No Barbara: Good. Issue can be removed. -------------- Source-Specific Routing for Babel, Matthieu Boutier Presented slides: https://www.ietf.org/proceedings/99/slides/slides-99-babel-source-specific-routing-00.pdf Toke: I like this. David: Great work. Support adopting. Juliusz: Dumpt the dump. Donald: We will determine if there is consensus for adoption. -------------- BIER in Babel, Zheng Zhang Presented slides: https://www.ietf.org/proceedings/99/slides/slides-99-babel-bier-in-babel-00.pdf Alia Atlas: Doc should be in BABEL if there is interest. Because BABEL is still moving and knowledge is broad. Juliusz: Very interesting work, but not necessarily interesting from perspective of application. It would be used by data center or operator. Curious as to how difficult it would be to implement BIER when you only have the partial view that BABEL gives you. Next question is I'm uncomfortable with sub-sub-TLV. Is the needed TLV widely implemented? Not sure since focus has been on BABEL for homenet. That makes me wary of adoption. Denis Ovsienko spoke remotely regarding github implementation.