Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at VTEP

Anoop Ghanwani <anoop@alumni.duke.edu> Thu, 10 October 2019 21:33 UTC

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From: Anoop Ghanwani <anoop@alumni.duke.edu>
Date: Thu, 10 Oct 2019 14:33:38 -0700
Message-ID: <CA+-tSzx0vOmDj3vOH3S=jQ2bq6GGjz=GB1qVM2f8sucA_LwHXw@mail.gmail.com>
Subject: Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at VTEP
To: xiao.min2@zte.com.cn
Cc: draft-ietf-bfd-vxlan@ietf.org, nvo3@ietf.org, rtg-bfd WG <rtg-bfd@ietf.org>
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Hi Xiao Min,

Can you provide more detail on your scenario?  I'm having trouble figuring
it out from the description below.  I need to know what subnets the tenants
are in.

Anoop

On Thu, Oct 10, 2019 at 5:00 AM <xiao.min2@zte.com.cn> wrote:

> Hi Anoop,
>
>
> Please see my response inline with [XM].
> 原始邮件
> *发件人:*AnoopGhanwani <anoop@alumni.duke.edu>
> *收件人:*肖敏10093570;
> *抄送人:*draft-ietf-bfd-vxlan@ietf.org <draft-ietf-bfd-vxlan@ietf.org>rg>;
> nvo3@ietf.org <nvo3@ietf.org>;rtg-bfd WG <rtg-bfd@ietf.org>rg>;
> *日 期 :*2019年10月10日 15:47
> *主 题 :**Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at VTEP*
> _______________________________________________
> nvo3 mailing list
> nvo3@ietf.org
> https://www.ietf.org/mailman/listinfo/nvo3
>
> Hi Xiao Min,
>
> In those cases, the term "VN" is used to talk about multiple IP interfaces
> in a VRF.  The different interfaces would have to be different VNIs.
>
> [XM] To be clear, I interpret VNI as Virtual Network Identifier that
> should be present within VxLAN/Geneve header. Do you mean in the case
> multiple Tenant Systems connect to multiple NVEs through IP routing
> network, different NVEs must encapsulate different Virtual Network
> Identifiers?
>
> In the mixed case (with MPLS and L2 hitting the NVE at different VAPs),
> I'm not sure how it would work in the same VNI.  If you think it's
> important, I think it may be worth writing it up.  If there's enough merit
> in the use case, we can figure out how to run multiple BFD sessions on the
> same VNI.
>
> [XM] As to the mixed case, I don't know whether there's enough merit, I
> just raise it for discussion because it seems not being prohibited from the
> NVO3 architecture point of view.
>
>
> Anoop
>
>
> Best Regards,
>
> Xiao Min
>
>
> On Wed, Oct 9, 2019 at 11:06 PM <xiao.min2@zte.com.cn> wrote:
>
>> Hi Anoop,
>>
>>
>> Normally, it is. While Tenant Systems connect to NVE through IP routing
>> network or MPLS forwarding network, it is not.
>>
>>
>> Best Regards,
>>
>> Xiao Min
>> 原始邮件
>> *发件人:*AnoopGhanwani <anoop@alumni.duke.edu>
>> *收件人:*肖敏10093570;
>> *抄送人:*draft-ietf-bfd-vxlan@ietf.org <draft-ietf-bfd-vxlan@ietf.org>rg>;
>> nvo3@ietf.org <nvo3@ietf.org>;rtg-bfd WG <rtg-bfd@ietf.org>rg>;
>> *日 期 :*2019年10月10日 05:33
>> *主 题 :**Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at VTEP*
>> Hi Xiao Min,
>> Normally, I think of a VNI as a broadcast domain.  The only way I can
>> make sense of the picture below is to have a separate VNI for each MPLS
>> interface on the NVE.
>>
>> Anoop
>>
>> On Tue, Oct 8, 2019 at 11:09 PM <xiao...min2@zte.com.cn
>> <xiao.min2@zte.com.cn>> wrote:
>>
>>> Hi Anoop,
>>>
>>>
>>> In this use case there is no forwarding happens between the MPLS and
>>> non-MPLS parts, would this use case be prohibited?
>>>
>>> If the answer is yes, then I agree that all Tenant Systems attached to a
>>> common NVE MUST share a VAP so long as they connect to the same VN,
>>> although in RFC8014 it uses "can" but not "MUST". As a result, we should
>>> not allow multiple BFD sessions for the same VNI between two NVEs.
>>>
>>> If the answer is no, then we should allow multiple BFD sessions for the
>>> same VNI between two NVEs. I personally lean to this answer.
>>>
>>>
>>> Best Regards,
>>>
>>> Xiao Min
>>> 原始邮件
>>> *发件人:*AnoopGhanwani <anoop@alumni.duke.edu>
>>> *收件人:*肖敏10093570;
>>> *抄送人:*Greg Mirsky <gregimirsky@gmail.com>;didutt@gmail.com <
>>> didutt@gmail.com>;draft-ietf-bfd-vxlan@ietf.org <
>>> draft-ietf-bfd-vxlan@ietf.org>;nvo3@ietf.org <nvo3@ietf.org>rg>;
>>> santosh...pallagatti@gmail.com <santosh.pallagatti@gmail.com> <
>>> santosh.pallagatti@gmail.com>;rtg-bfd WG <rtg-bfd@ietf.org>;Joel M.
>>> Halpern <jmh@joelhalpern.com>;tsridhar@vmware.com <tsridhar@vmware.com>om>;
>>> *日 期 :*2019年10月09日 06:28
>>> *主 题 :**Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at VTEP*
>>> Hi Xiao Min,
>>> The picture doesn't have enough information to explain why they are in
>>> the same VNI, and exactly how forwarding happens between the MPLS and
>>> non-MPLS parts.
>>>
>>> Anoop
>>>
>>> On Tue, Oct 8, 2019 at 12:31 AM <xiao.min2@zte.com.cn> wrote:
>>>
>>>> Hi Anoop,
>>>>
>>>>
>>>> I don't know such a draft that describes MPLS over Geneve, but I
>>>> believe the following figure derived from figure 1 of RFC8014 would help,
>>>> in the following figure Tenant System1, Tenant System2, Tenant System3 and
>>>> Tenant System4 are assumed belonging to the same VNI, so two BFD sessions
>>>> for the same VNI need to be run between NVE1 and NVE2.
>>>>
>>>>                                             +--------+
>>>>                                        +----| Tenant |
>>>>                                      ( ' )  | System1|
>>>>             ................       ( MPLS ) +--------+
>>>>             .              .  +--+-+ ( _ )
>>>>             .              .--|NVE1|---+
>>>>             .              .  |    |
>>>>             .              .  +--+-+
>>>>             .              .     |
>>>>             .  L3 Overlay  .   ( ' )
>>>>             .    Network   . (Ethernet)
>>>>             .              .   ( _ )
>>>>             .              .     |
>>>>             ................    +--------+
>>>>                |                | Tenant |
>>>>              +----+             | System2|
>>>>              |NVE2|             +--------+
>>>>              |    |--------+
>>>>              +----+        |
>>>>                |           |
>>>>              ( ' )       ( ' )
>>>>            ( MPLS )    (Ethernet)
>>>>              ( _ )       ( _ )
>>>>                |           |
>>>>            +--------+  +--------+
>>>>            | Tenant |  | Tenant |
>>>>            | System3|  | System4|
>>>>            +--------+  +--------+
>>>>
>>>>
>>>> Best Regards,
>>>>
>>>> Xiao Min
>>>> 原始邮件
>>>> *发件人:*AnoopGhanwani <anoop@alumni...duke.edu <anoop@alumni.duke.edu>>
>>>> *收件人:*肖敏10093570;
>>>> *抄送人:*Greg Mirsky <gregimirsky@gmail.com>;didutt@gmail...com
>>>> <didutt@gmail.com> <didutt@gmail.com>;draft-ietf-bfd-vxlan@ietf.org <
>>>> draft-ietf-bfd-vxlan@ietf.org>;nvo3@ietf.org <nvo3@ietf.org>rg>;
>>>> santosh.pallagatti@gmail.com <santosh.pallagatti@gmail.com>;rtg-bfd WG
>>>> <rtg-bfd@ietf.org>;Joel M. Halpern <jmh@joelhalpern.com>om>;
>>>> tsridhar@vmware.com <tsridhar@vmware.com>om>;
>>>> *日 期 :*2019年10月08日 12:15
>>>> *主 题 :**Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at VTEP*
>>>> Hi Xiao Min,
>>>> Is there a draft that describes MPLS over Geneve?  It sounds like the
>>>> NVE is an MPLS router in this case and if you're using the same VNI as you
>>>> switch MPLS, then it's a one-armed router.  That doesn't change how BFD
>>>> needs to be run between NVEs.
>>>>
>>>> Anoop
>>>>
>>>> On Mon, Oct 7, 2019 at 7:28 PM <xiao.min2@zte.com.cn> wrote:
>>>>
>>>>> Hi Anoop,
>>>>>
>>>>>
>>>>> Sorry for the late response, I just come back from vacation.
>>>>>
>>>>> The use case is that the network between the VM and the NVE is an MPLS
>>>>> network, within which the packet is forwarded basing on MPLS label, but not
>>>>> Ethernet MAC address and/or 802.1Q VLAN. When two such kind of MPLS
>>>>> networks need to communicate with each other, through a Geneve tunnel, the
>>>>> encap I illustrated would be used.
>>>>>
>>>>>
>>>>> Best Regards,
>>>>>
>>>>> Xiao Min
>>>>> 原始邮件
>>>>> *发件人:*AnoopGhanwani <anoop@alumni.duke.edu>
>>>>> *收件人:*肖敏10093570;
>>>>> *抄送人:*Greg Mirsky <gregimirsky@gmail.com>;didutt@gmail.com <
>>>>> didutt@gmail.com>;draft-ietf-bfd-vxlan@ietf.org <
>>>>> draft-ietf-bfd-vxlan@ietf.org>;nvo3@ietf.org <nvo3@ietf.org>rg>;
>>>>> santosh.pallagatti@gmail.com <santosh.pallagatti@gmail.com>;rtg-bfd
>>>>> WG <rtg-bfd@ietf.org>;Joel M. Halpern <jmh@joelhalpern...com
>>>>> <jmh@joelhalpern.com>>;tsridhar@vmware.com <tsridhar@vmware.com>om>;
>>>>> *日 期 :*2019年09月28日 05:36
>>>>> *主 题 :**Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at
>>>>> VTEP*
>>>>> Hi Xiao Min,
>>>>> Thanks for the details about the encap but the use case is not clear.
>>>>> It might help if you explain why its necessary to map a physical Ethernet
>>>>> port and/or 802.1Q VLAN to the same VNI as an MPLS packet without an L2
>>>>> header.
>>>>>
>>>>> Thanks,
>>>>> Anoop
>>>>>
>>>>> On Thu, Sep 26, 2019 at 7:50 PM <xiao.min2@zte.com.cn> wrote:
>>>>>
>>>>>> Hi Anoop,
>>>>>>
>>>>>>
>>>>>> Due to the fact that a variety of Tunnels could be used under the
>>>>>> NVO3 architecture, as an example, below figure illustrates the
>>>>>> format of MPLS packet over Geneve Tunnel.
>>>>>>
>>>>>>     0                   1                   2                   3
>>>>>>     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
>>>>>>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>>>>>    |                                                               |
>>>>>>    ~                      Outer Ethernet Header                    ~
>>>>>>    |                                                               |
>>>>>>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>>>>>    |                                                               |
>>>>>>    ~                        Outer IPvX Header                      ~
>>>>>>    |                                                               |
>>>>>>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>>>>>    |                                                               |
>>>>>>    ~                        Outer UDP Header                       ~
>>>>>>    |                                                               |
>>>>>>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>>>>>    |                                                               |
>>>>>>    ~                          Geneve Header                        ~
>>>>>>    |                                                               |
>>>>>>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
>>>>>>    |                                                               |  |
>>>>>>    ~                         MPLS Label Stack                      ~  M
>>>>>>    |                                                               |  P
>>>>>>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  L
>>>>>>    |                                                               |  S
>>>>>>    |                                                               |
>>>>>>    ~                             Payload                           ~  P
>>>>>>    |                                                               |  K
>>>>>>    |                                                               |  T
>>>>>>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
>>>>>>    |                               FCS                             |
>>>>>>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>>>>>>
>>>>>>
>>>>>> Note that in NVO3 working group Greg and I have submitted an
>>>>>> individual draft draft-xiao-nvo3-bfd-geneve, which is used to address BFD
>>>>>> over Geneve.
>>>>>>
>>>>>> The intention is to make the two drafts draft-ietf-bfd-vxlan and
>>>>>> draft-xiao-nvo3-bfd-geneve aligned, that is to say, we try to define the
>>>>>> identical mechanism for the common part of BFD over VxLAN Tunnel and BFD
>>>>>> over Geneve Tunnel. For the common part, draft-xiao-nvo3-bfd-geneve would
>>>>>> reference to draft-ietf-bfd-vxlan, and for the other part specific to
>>>>>> Geneve, we'll define the specific mechanism in draft-xiao-nvo3-bfd-geneve.
>>>>>>
>>>>>>
>>>>>> Hope that clarifies.
>>>>>>
>>>>>>
>>>>>> Best Regards,
>>>>>>
>>>>>> Xiao Min
>>>>>> 原始邮件
>>>>>> *发件人:*AnoopGhanwani <anoop@alumni.duke.edu>
>>>>>> *收件人:*肖敏10093570;
>>>>>> *抄送人:*Greg Mirsky <gregimirsky@gmail.com>;didutt@gmail.com
>>>>>> <didutt@gmail...com> <didutt@gmail.com>;draft-ietf-bfd-vxlan@ietf.org
>>>>>> <draft-ietf-bfd-vxlan@ietf.org>;nvo3@ietf.org <nvo3@ietf.org>rg>;
>>>>>> santosh.pallagatti@gmail.com <santosh.pallagatti@gmail.com>;rtg-bfd
>>>>>> WG <rtg-bfd@ietf.org>;Joel M. Halpern <jmh@joelhalpern.com>om>;
>>>>>> tsridhar@vmware.com <tsridhar@vmware...com <tsridhar@vmware.com>>m>>;
>>>>>> bfd-chairs@ietf.org <bfd-chairs@ietf.org>rg>;
>>>>>> *日 期 :*2019年09月26日 23:16
>>>>>> *主 题 :**Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at
>>>>>> VTEP*
>>>>>> Hi Xiao Min,
>>>>>> I think we would need more detail around the use case below.  What
>>>>>> does the MPLS packet over Tunnel look like?
>>>>>>
>>>>>> Thanks,
>>>>>> Anoop
>>>>>>
>>>>>> On Wed, Sep 25, 2019 at 11:37 PM <xiao.min2@zte.com.cn> wrote:
>>>>>>
>>>>>>> Hi Anoop,
>>>>>>>
>>>>>>>
>>>>>>> Thanks for your comments.
>>>>>>>
>>>>>>> Considering a scenario where TS1 has an MPLS access (i.e.
>>>>>>> MPLS-Packet over Tunnel between NVEs) to VNI1, TS3 has an Ethernet access
>>>>>>> (i.e. MAC-Frame over Tunnel between NVEs) to VNI1, then how can TS1 and TS3
>>>>>>> share one VAP?
>>>>>>>
>>>>>>>
>>>>>>> Best Regards,
>>>>>>>
>>>>>>> Xiao Min
>>>>>>> 原始邮件
>>>>>>> *发件人:*AnoopGhanwani <anoop@alumni.duke.edu>
>>>>>>> *收件人:*肖敏10093570;
>>>>>>> *抄送人:*Greg Mirsky <gregimirsky@gmail.com>;didutt@gmail.com <
>>>>>>> didutt@gmail.com>;draft-ietf-bfd-vxlan@ietf.org <
>>>>>>> draft-ietf-bfd-vxlan@ietf.org>;nvo3@ietf.org <nvo3@ietf.org>rg>;
>>>>>>> santosh.pallagatti@gmail.com <santosh.pallagatti@gmail.com>;rtg-bfd
>>>>>>> WG <rtg-bfd@ietf.org>;Joel M. Halpern <jmh@joelhalpern.com>om>;
>>>>>>> tsridhar@vmware.com <tsridhar@vmware.com>;bfd-chairs@ietf.org <
>>>>>>> bfd-chairs@ietf.org>gt;;
>>>>>>> *日 期 :*2019年09月26日 08:36
>>>>>>> *主 题 :**Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at
>>>>>>> VTEP*
>>>>>>> _______________________________________________
>>>>>>> nvo3 mailing list
>>>>>>> nvo3@ietf.org
>>>>>>> https://www.ietf.org/mailman/listinfo/nvo3
>>>>>>>
>>>>>>> >>>
>>>>>>> Some people may argue that all Tenant Systems connecting to the same
>>>>>>> Virtual Network MUST share one VAP, if that's true, then VAP1 and VAP3
>>>>>>> should merge into one VAP and my explanation doesn't work. Copying to NVO3
>>>>>>> WG to involve more experts, hope for your clarifications and comments.
>>>>>>> >>>
>>>>>>>
>>>>>>> I would be one of those that would argue that they MUST share on VAP
>>>>>>> if they connect to the same Virtual Network.  IMO, the NVO3 arch doc should
>>>>>>> have been clearer about this.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Anoop
>>>>>>>
>>>>>>> On Tue, Sep 24, 2019 at 7:40 PM <xiao.min2@zte.com.cn> wrote:
>>>>>>>
>>>>>>>> Hi Santosh,
>>>>>>>>
>>>>>>>>
>>>>>>>> With regard to the question whether we should allow multiple BFD
>>>>>>>> sessions for the same VNI or not, IMHO we should allow it, more explanation
>>>>>>>> as follows...
>>>>>>>>
>>>>>>>> Below is a figure derived from figure 2 of RFC8014 (An
>>>>>>>> Architecture for Data-Center Network Virtualization over Layer 3 (NVO3)
>>>>>>>> ).
>>>>>>>>
>>>>>>>>                     |         Data Center Network (IP)        |
>>>>>>>>                     |                                         |
>>>>>>>>                     +-----------------------------------------+
>>>>>>>>                          |                           |
>>>>>>>>                          |       Tunnel Overlay      |
>>>>>>>>             +------------+---------+       +---------+------------+
>>>>>>>>             | +----------+-------+ |       | +-------+----------+ |
>>>>>>>>             | |  Overlay Module  | |       | |  Overlay Module  | |
>>>>>>>>             | +---------+--------+ |       | +---------+--------+ |
>>>>>>>>             |           |          |       |           |          |
>>>>>>>>      NVE1   |           |          |       |           |          | NVE2
>>>>>>>>             |  +--------+-------+  |       |  +--------+-------+  |
>>>>>>>>             |  |VNI1 VNI2  VNI1 |  |       |  | VNI1 VNI2 VNI1 |  |
>>>>>>>>             |  +-+-----+----+---+  |       |  +-+-----+-----+--+  |
>>>>>>>>             |VAP1| VAP2|    | VAP3 |       |VAP1| VAP2|     | VAP3|
>>>>>>>>             +----+-----+----+------+       +----+-----+-----+-----+
>>>>>>>>                  |     |    |                   |     |     |
>>>>>>>>                  |     |    |                   |     |     |
>>>>>>>>                  |     |    |                   |     |     |
>>>>>>>>           -------+-----+----+-------------------+-----+-----+-------
>>>>>>>>                  |     |    |     Tenant        |     |     |
>>>>>>>>             TSI1 | TSI2|    | TSI3          TSI1| TSI2|     |TSI3
>>>>>>>>                 +---+ +---+ +---+             +---+ +---+   +---+
>>>>>>>>                 |TS1| |TS2| |TS3|             |TS4| |TS5|   |TS6|
>>>>>>>>                 +---+ +---+ +---+             +---+ +---+   +---+
>>>>>>>>
>>>>>>>> To my understanding, the BFD sessions between NVE1 and NVE2 are
>>>>>>>> actually initiated and terminated at VAP of NVE.
>>>>>>>>
>>>>>>>> If the network operator want to set up one BFD session between VAP1
>>>>>>>> of NVE1 and VAP1of NVE2, at the same time another BFD session between VAP3
>>>>>>>> of NVE1 and VAP3 of NVE2, although the two BFD sessions are for
>>>>>>>> the same VNI1, I believe it's reasonable, so that's why I think we
>>>>>>>> should allow it.
>>>>>>>>
>>>>>>>>
>>>>>>>> Of course, in RFC8014 it also says:
>>>>>>>>
>>>>>>>> "Note that two different Tenant Systems (and TSIs) attached to a common NVE can share a VAP (e.g., TS1 and TS2 in Figure 2) so long as they connect to the same Virtual Network."
>>>>>>>>
>>>>>>>> Some people may argue that all Tenant Systems connecting to the
>>>>>>>> same Virtual Network MUST share one VAP, if that's true, then VAP1 and VAP3
>>>>>>>> should merge into one VAP and my explanation doesn't work. Copying to NVO3
>>>>>>>> WG to involve more experts, hope for your clarifications and comments.
>>>>>>>>
>>>>>>>>
>>>>>>>> Best Regards,
>>>>>>>>
>>>>>>>> Xiao Min
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>> _______________________________________________
>>> nvo3 mailing list
>>> nvo3@ietf.org
>>> https://www.ietf.org/mailman/listinfo/nvo3
>>>
>>
>>
>