Hi Shahram, Agree that running a separate session for each VNI is not going to be scalable. But the current draft only allows implementations to provide such a functionality. Implementations may choose to run a separate BFD session for a select set of VNIs (prioritise a select few) and so we do not want to preclude this possibility. We will leave it to implementations on which VNIs require this.
May be we can rephrase the following in the draft under Section Deployment to avoid confusion. Replace this Separate BFD sessions can be established between the VTEPs (IP1 and IP2) for monitoring each of the VXLAN tunnels (VNI 100 and 200). With Separate BFD sessions MAY be established between the VTEPs (IP1 and IP2) for monitoring each of the VXLAN tunnels (VNI 100 and 200). Thanks Regards Mallik On 26/06/15 12:49, "Santosh P K" <[email protected]> wrote: >Hello Shahram, > Thanks a lot for your comments. Indeed "VXLAN tunnel" is confusing, >what we are trying to do here is address the requirement from draft " >https://tools.ietf.org/id/draft-ashwood-nvo3-operational-requirement-03.tx >t". Here we have a requirement for running proactive OAM between NV edge >to NV edge per VNI. This is an individual draft for now. > >Thanks >Santosh P K > >> -----Original Message----- >> From: Shahram Davari [mailto:[email protected]] >> Sent: Thursday, June 25, 2015 8:18 PM >> To: Santosh P K; Gregory Mirsky; Vengada Prasad Govindan (venggovi); >> MALLIK MUDIGONDA (mmudigon) >> Cc: [email protected] >> Subject: RE: New Version Notification for >>draft-spallagatti-bfd-vxlan-00.txt >> >> Hi Santosh, >> >> I think you probably have misunderstood the use of OAM/BFD in general. >> VXLAN is not a networking layer, rather it is a service demultiplexer >>(service >> identifier). I think the misunderstanding might be from the name "VXLAN >> tunnel". Since VXLAN is not a tunnel. The tunnel is actually an IP >>tunnel that >> has VXLAN as service identifier. >> >> A single IP tunnel can carry many VXLANs. Not only doing BFD per VXLAN >> doesn't make sense, but it is also not scalable. My suggestion is do >>BFD for >> the IP tunnel and you can achieve what you want. >> >> Thx >> Shahram >> >> -----Original Message----- >> From: Rtg-bfd [mailto:[email protected]] On Behalf Of Santosh P K >> Sent: Monday, May 25, 2015 5:43 AM >> To: Gregory Mirsky; Vengada Prasad Govindan (venggovi); MALLIK >> MUDIGONDA (mmudigon) >> Cc: [email protected] >> Subject: RE: New Version Notification for >>draft-spallagatti-bfd-vxlan-00.txt >> >> Greg, >> Thanks a lot for your review comments. Please see my inline comments. >> >> >you reference RFC 5880 but don't specify which of defined in BFD base >> document modes are in scope of this work. I assume that, like in RFC >>5884, it >> is only Asynchronous mode and Section 7 excludes Echo BFD but Demand >> mode not mentioned. >Making >more explicit statement would be helpful. >> >> Sure we can add text for Demand mode as well. >> >> >> >section 2: >> >I think that these three cases hardly apply to the proposed solution. >>In >> particular, BFD may very coarsely localize path failure as we should >> remember that path and remote peer failure are undistinguishable. Thus >> failure detected at one VM, with Tunnel >BFD session operational, >>cannot be >> interpreted as peer VM failure. >> >> I am sorry I did not understand this, can you please elaborate more on >>this? >> >> >section 3: >> >what ensures that reverse direction of the BFD session between IP1 >> (ingress) and IP2 (egress) , i.e. egress transmits BFD control packets >>toward >> the ingress, uses the same tunnel traversed by BFD control packets sent >> from ingress toward the egress? >Perhaps use of BFD Reverse Path TLV and >> BFD Discriminator TLV may be one solution? >> >> In case of IP if reverse path has multiple paths to a destination then >>taking a >> particular path means IP header stacking? Correct me if I am wrong. >> >> >Perhaps this section could be the right place to discuss and define >>behavior >> of the egress in terms of its role in BFD session: >> >packet encapsulation; >> >failure reporting; >> >path selection (discussed above). >> >And the issues of the encapsulation, reverse path selection are >>relevant for >> S-BFD scenario as well (I think that Prasad's suggestion to split into >>two >> documents, BFD and S-BFD, is quite reasonable). >> >> If all the above point has different methods for BFD and S-BFD then of >>course >> we should spilt the draft in to two. >> >> >section 6.1: >> >considering 5884clarification work, can multiple BFD session operate >> between IP1 and IP2 over the same tunnel? >> >> I do not see a case where we need multiple BFD session between IP pair >> when BFD session terminates at VTEP itself. >> >> >> Thanks >> Santosh P K >> >> >> >> -----Original Message----- >> From: Rtg-bfd [mailto:[email protected]] On Behalf Of Vengada >> Prasad Govindan (venggovi) >> Sent: Friday, May 08, 2015 12:39 AM >> To: Santosh P K; MALLIK MUDIGONDA (mmudigon) >> Cc: [email protected] >> Subject: RE: New Version Notification for >>draft-spallagatti-bfd-vxlan-00.txt >> >> Hello Santosh/ Authors, >> Thanks for your prompt considerations of the comments submitted in this >> thread. I request you to consider the following points for discussion: >> 1) Fig 3 of draft-ashwood-nvo3-oam-requirements provides the context for >> OAM layering in NVO3. Though, an individual draft at the moment, I >>submit >> that we consider this for providing more context to the discussion here. >> 2) Per my understanding of your proposal, the intent is to use BFD for >>OAM >> at the NV edge layer. Please let me know if this understanding is >>incorrect. >> 3) The clarifications requested earlier this thread concern about the >>inner IP >> address (SIP in particular) of the BFD packet . Would they be used from >>the >> overlay IP address space (belonging to the tenant). If this is the >>case, what >> would the difference between a BFD session using the tenant IP (at the >>NV >> edge), a particular VNI, and that of a service layer OAM session that >>can be >> run using single-hop BFD (RFC 5880). >> In other words, how can the OAM (BFD in this case) operating at the NV >>Edge >> layer operate without using IP from the Tenant layer if the packet is >>required >> to be VxLAN encapsulated? >> Thanks >> Prasad >> >> -----Original Message----- >> From: Santosh P K [mailto:[email protected]] >> Sent: Wednesday, May 06, 2015 3:03 PM >> To: MALLIK MUDIGONDA (mmudigon) >> Cc: Vengada Prasad Govindan (venggovi); [email protected] >> Subject: RE: New Version Notification for >>draft-spallagatti-bfd-vxlan-00.txt >> >> Mallik, >> Thanks for your review comments. >> >> >> >1. It is not clear if this draft is addressing both VM to VM and VTEP >>to VTEP >> verification through BFD. I assume it is both. >> >> Draft is applicable only for VTEP to VTEP, for VM to VM (if VM is L3 >>aware) >> BFD as per RFC 5880/5881 should work as it is. VM's will not be aware >>of any >> tunnel. Draft talks about tunnel verification which terminates at >>VTEP's. >> >> >2. If the VMs are Layer 2 only, then what is the inner IP address >> >(especially source IP)? I understand that outer IP is going to carry >>the VTEPs >> addresses. >> >> As mentioned in the draft it would be outgoing interface IP sending >>VTEP. >> >> >3. Why is the inner IP destination address 127/8 or >>0:0:0:0:0:FFFF:7F00/104? >> I understand that it is to avoid the packet being routed but, how can >>an IP >> packet addressed to a particular VTEP be consumed by any other node in >>the >> network and then route the inner >payload? >> >> The same argument holds true for MPLS as well right? The motivation for >> using the address range 127/8 is the same as described in Section 2.1 of >> RFC4379. >> >> >4. The service node's use case is not very clear. Mat be you can add a >>little >> bit of details here. >> >> Yes, we can do that. >> >> >5. I understand that VTEP knows that the packet is to be terminated at >>the >> VTEP based on TTL being 1. What about the case of VM to VM BFD? What >> should be the TTL value here? Is it 255 or something different? It is >> hardcoded to "1" in the draft. >> >> VM's will use normal Async BFD so will use TTL 255. >> >> >6. Since we are using a destination UDP port of 3784, shouldn't the TTL >> >be 255 to be consistent with the RFC 5880? >> >> Section 7 of RFC 5884 also mentions use of IP TTL set to 1 whereas UDP >>port >> number set to 3784. >> >> >> Thanks >> Santosh P K >> >> >> >> From: "Vengada Prasad Govindan (venggovi)" <[email protected]> >> Date: Wednesday, 6 May 2015 9:39 am >> To: Santosh P K <[email protected]>, "[email protected]" <rtg- >> [email protected]> >> Subject: RE: New Version Notification for >>draft-spallagatti-bfd-vxlan-00.txt >> >> Hello Santosh/ Authors, >> Thanks for sharing the document, please find a few thoughts below. >> 1. The current document talks about both BFD and S-BFD - would it be >> beneficial to make separate documents for BFD and SBFD to maintain >> consistency with the current set of documents. >> 2. Motivation: It would be nice to state the requirements or motivation >>that >> this draft addresses, i.e. what problems does this draft address that >>cannot >> be solved using the existing BFD/ SBFD protocol treating the VxLAN as a >> tunnel/ underlay transport transparent to BFD. I would submit that BFD >>over >> VxLAN not be treated along the same lines of BFD over MPLS or BFD for PW >> (VCCV) given the differences in the nature of the transport between MPLS >> and VxLAN. >> 3. Inner Ethernet header: The document does not address the contents of >> the Inner Ethernet header (present after the VxLAN header). This needs >>to >> be specified. >> 4. Destination IP: The document mandates that this needs to be 127/8. >>What >> disadvantages do you observe if the DIP were to be the IP of the >>destination >> VTEP? When using 127/8 as the DIP. one problem is that there is no >>indication >> of the intended DIP of the BFD session by using 127/8. What if the node >>at >> which the VxLAN tunnel is (prematurely) terminated happens to support >> BFD? It may be better to use the IP address of the Destination VTEP as >>the >> DIP. >> 5. Inner TTL: For the same reasons discussed in (2), why does the >>document >> mandate this to be set to 1? >> 6. It may be beneficial to run a spell-checker to fix typos in the >>document. >> I request the authors/ WG to comment on the above aspects. >> Thanks >> Prasad >> >> >> -----Original Message----- >> From: Rtg-bfd [mailto:[email protected]] On Behalf Of Santosh P K >> Sent: Monday, May 04, 2015 10:55 PM >> To: [email protected] >> Subject: FW: New Version Notification for >>draft-spallagatti-bfd-vxlan-00.txt >> >> Hello All, >> A new BFD for VXLAN draft has been submitted. Please do review and >>get >> back to us with any comments/feedback. >> >> Thanks >> Santosh P K >> >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] >> Sent: Monday, May 04, 2015 9:29 PM >> To: Basil Saji; Santosh P K; Sudarsan Paragiri Mohan; Santosh P K; >>Basil Saji; >> Sudarsan Paragiri Mohan >> Subject: New Version Notification for >> draft-spallagatti-bfd-vxlan-00.txt >> A new version of I-D, draft-spallagatti-bfd-vxlan-00.txt >> has been successfully submitted by Santosh Pallagatti and posted to the >>IETF >> repository. >> Name: draft-spallagatti-bfd-vxlan >> Revision: 00 >> Title: BFD for VXLAN >> Document date: 2015-05-04 >> Group: Individual Submission >> Pages: 9 >> URL: >>https://www.ietf.org/internet-drafts/draft-spallagatti-bfd-vxlan- >> 00.txt >> Status: >>https://datatracker.ietf.org/doc/draft-spallagatti-bfd-vxlan/ >> Htmlized: >>https://tools.ietf.org/html/draft-spallagatti-bfd-vxlan-00 >> Abstract: >> This document describes use of Bidirectional Forwarding Detection >> (BFD) protocol for VXLAN . Comments on this draft should be directed >> to [email protected]. >> Please note that it may take a couple of minutes from the time of >>submission >> until the htmlized version and diff are available at tools.ietf.org. >> The IETF Secretariat >> >> >> >
