I also agree with Joel. -- Jeff
> On Oct 31, 2019, at 11:59 AM, Joel M. Halpern <j...@joelhalpern.com> wrote: > > Explicitly restricting the discard behavior to the management VNI takes care > of my concern. > > Thank you, > Joel > > On 10/31/2019 11:48 AM, Greg Mirsky wrote: >> Hi Jeff, >> thank you for the detailed clarification of your questions. Please find my >> follow-up notes in-lined tagged GIM2>>. >> Regards, >> Greg >> On Wed, Oct 30, 2019 at 2:14 PM Jeffrey Haas <jh...@pfrc.org >> <mailto:jh...@pfrc.org>> wrote: >> Greg, >> On Wed, Oct 30, 2019 at 01:58:30PM -0700, Greg Mirsky wrote: >> > On Wed, Oct 30, 2019 at 1:27 PM Jeffrey Haas <jh...@pfrc.org >> <mailto:jh...@pfrc.org>> wrote: >> > >> > > Greg, >> > > >> > > From the updated text: >> > > >> > > "At the same time, a service layer BFD session may be used >> between the >> > > tenants of VTEPs IP1 and IP2 to provide end-to-end fault >> management. In >> > > such case, for VTEPs BFD Control packets of that session are >> > > indistinguishable from data packets. If end-to-end defect >> detection is >> > > realized as the set of concatenated OAM domains, e.g., VM1-1 - >> IP1 -- >> > > IP2 - VM2-1, then the BFD session over VXLAN between VTEPs SHOULD >> > > follow the procedures described in Section 6.8.17 [RFC5880]." >> > > >> > > In the case that two VMs are running BFD to each other as a user >> > > application >> > > rather than as part of the virtualized environment, it's >> unlikely that >> > > they'd be treated as concatenated domains. To do so, the >> tenant VMs would >> > > have to have a sense that they are indeed virtual. >> > > >> > > Is your intent in this text that BFD implementations on the >> server should >> > > detect BFD sessions between servers and change them to a >> concatenated >> > > session? >> > > >> > GIM>> No, we do not suggest that the concatenation of BFD sessions be >> > automagical. That may be controlled via the management plane though. >> Then my suggestion is we may not want this text. >> It's fine to say "if tenants want to run BFD to each other, and that is >> standard BFD (RFC 5881) from the perspective of those tenants" if that's >> your intent. Leave automagic out of the spec. :-) >> GIM2>> I'd take the passage referring to the concatenated path out. That >> will leave it as: >> At the same time, a service layer BFD session may be used between the >> tenants of VTEPs IP1 and IP2 to provide end-to-end fault management. >> In such case, for VTEPs BFD Control packets of that session are >> indistinguishable from data packets. >> > > Section 5 comment: >> > > >> > > : The UDP destination port and the TTL of the inner IP packet >> MUST be >> > > : validated to determine if the received packet can be >> processed by >> > > : BFD. BFD Control packets with unknown MAC address MUST NOT be >> > > : forwarded to VMs. >> > > >> > > I'd suggest pushing the second sentence into the prior section >> since it >> > > deals with MAC addresses rather than the UDP procedures. >> > > >> > GIM>> Could you please clarify your suggestion - move to Section >> 4 or to >> > the preceding paragraph? I think it is the latter but wanted to >> make sure. >> Full section 5 from your draft-8 candidate: >> : 5. Reception of BFD Packet from VXLAN Tunnel >> : >> : Once a packet is received, the VTEP MUST validate the packet. If >> the >> : Destination MAC of the inner Ethernet frame matches one of the MAC >> : addresses associated with the VTEP the packet MUST be processed >> : further. If the Destination MAC of the inner Ethernet frame >> doesn't >> : match any of VTEP's MAC addresses, then the processing of the >> : received VXLAN packet MUST follow the procedures described in >> : Section 4.1 [RFC7348]. >> It's not clear what that procedure is, with respect to BFD. Section 4.1 >> basically says is that when a mapping is discovered, deliver it to >> that VM >> with headers removed. >> Section 4.1 really doesn't discuss dropping behavior. >> : >> : The UDP destination port and the TTL of the inner IP packet MUST be >> : validated to determine if the received packet can be processed by >> : BFD. >> This is fine. >> : BFD Control packets with unknown MAC address MUST NOT be >> : forwarded to VMs. >> This appears to be clarifying the missing point in the prior >> paragraph. If >> that's the case, why is this sentence not part of the prior paragraph? >> GIM>> So I thought. Moving the sentence to the first paragraph highlighted >> the contradiction others had pointed earlier: >> On the one hand: >> If the Destination MAC of the inner Ethernet frame doesn't >> match any of VTEP's MAC addresses, then the processing of the >> received VXLAN packet MUST follow the procedures described in >> Section 4.1 [RFC7348]. >> To which we add: >> BFD Control packets with unknown MAC address >> MUST NOT be forwarded to VMs. >> But the unknown MACs are treated as BUM according to the last paragraph in >> Section 4.2 of RFC 7348: >> Note that multicast frames and "unknown MAC destination" frames are >> also sent using the multicast tree, similar to the broadcast frames. >> In light of that, can this draft require that BFD packets with unknown MAC >> be dropped and not flooded over the corresponding to the VNI domain? I think >> that in addition to moving the sentence up the statement must be updated: >> OLD TEXT: >> BFD Control packets with unknown MAC address >> MUST NOT be forwarded to VMs. >> NEW TEXT: >> If the BFD session is using the Management VNI (Section 6), >> BFD Control packets with unknown MAC address >> MUST NOT be forwarded to VMs. >> Comments? Suggestions? >> -- Jeff
