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

[Anoop Ghanwani <[e-mail]>]

Hi Santosh,

That looks better and I'd be OK with that.

However, I think it would be better if we did something like:

Destination IP: See Section xx.

Where section xx contains the complete description about setting the
destination IP including:
- Use of the underlay VTEP address for VNI 0.
- Use of overlay VTEP address for any other VNI.
- In the absence of available overlay VTEP address, use of 127/8 or IPv6
equivalent and a note about the firewall issue when using such addresses.

Also, I'm not enough of a firewall expert, but is the issue related to
firewalls running off the VTEP only, or are there firewalls that peek in
the inner header?  If there are the latter, then I think the text should be
more generic and just say something like "firewalls that examine the inner
header..." instead of "firewall running on the VTEP..." which is probably
not even technically correct, since the firewall doesn't run on the VTEP.

Anoop

On Mon, Oct 28, 2019 at 9:54 AM Santosh P K <[e-mail]>
wrote:

> Anoop,
>    You are right and Greg did remind me and it skipped my mind my bad.
>
> [Current text in section 4.0]
>
>       IP header:
>
>          Destination IP: IP address MUST NOT be of one of tenant's IP
>          addresses.  IP address MAY be selected from the range 127/8 for
>          IPv4, for IPv6 - from the range 0:0:0:0:0:FFFF:7F00:0/104.
>
>
> [proposed]
>
>
>       IP header:
>
>          Destination IP: IP address MUST NOT be of one of tenant's IP
>          addresses.  IP address MAY be set to VTEP IP address or it MAY be selected
>
>          from the range 127/8 for IPv4, for IPv6 - from the range 0:0:0:0:0:FFFF:7F00:0/104.
>
>                   The motivation for using the address range 127/8 is the same as specified in Section 2.1 of [RFC4379] <https://tools.ietf.org/html/rfc4379#section-2.1>.
>
>          This is an exception to the behavior defined in [RFC1122 <https://tools.ietf.org/html/rfc1122>].
>
>
>
> [proposed text for firewall]
>
> "As per section 4 inner destination IP address MAY be set to 127/8
> address. There could be firewall configured on VTEP to block 127/8 address
> range if set as destination IP in inner IP header. It is recommended to
> allow 127/8 range address through firewall only if inner IP header's
> destination IP is set to 127/8 IP address."
>
>
>
> Thanks
>
> Santosh P K
>
>
>
> On Mon, Oct 28, 2019 at 9:53 PM Anoop Ghanwani <[e-mail]>
> wrote:
>
>> Santosh,
>>
>> Does it have to be a MUST?  What if I am running IRB and there are IP
>> addresses per VNI assigned to the VTEPs?  Why can the operator not choose
>> to use those?
>>
>> Anoop
>>
>> On Mon, Oct 28, 2019 at 7:51 AM Santosh P K <[e-mail]>
>> wrote:
>>
>>> Dinesh, Anoop et all,
>>>      Lets us know if this text works for 127/8 address range?
>>>
>>> [proposed text for firewall]
>>>
>>> "As per section 4 inner destination IP address MUST be set to 127/8
>>> address. There may be firewall configured on VTEP to block 127/8 address
>>> range if set as destination IP in inner IP header. It is recommended to
>>> allow 127/8 range address through firewall only if 127/8 IP address is set
>>> as destination address in inner IP header."
>>>
>>>
>>> In section 4 we are talking about using 127/8 and not really giving
>>> reason why. I think we should have text as RFC 5884 has mentioned with
>>> below text.
>>>
>>> [From RFC 5884]
>>> " The motivation for using the address range 127/8 is the same as specified
>>> in Section 2.1 of [RFC4379]
>>> <https://tools.ietf.org/html/rfc4379#section-2.1>. This is an exception
>>> to the behavior defined in [RFC1122
>>> <https://tools.ietf.org/html/rfc1122>]."
>>>
>>>
>>>
>>> Thanks
>>> Santosh P K
>>>
>>>
>>>
>>> On Thu, Oct 24, 2019 at 1:24 AM Dinesh Dutt <[e-mail]> wrote:
>>>
>>>> Looks good to me Greg. I see that the text around the use of the inner
>>>> IP address as also quite acceptable. Will you add any words about the
>>>> firewall?
>>>>
>>>> Dinesh
>>>>
>>>> On Wed, Oct 23, 2019 at 8:36 PM, Greg Mirsky <[e-mail]>
>>>> wrote:
>>>>
>>>> Hi Dinesh, et al.,
>>>> please check the updated version that removed the reference to
>>>> Hypervisor in the text and Figure 1.
>>>>
>>>> Regards,
>>>> Greg
>>>>
>>>> On Wed, Oct 23, 2019 at 10:47 AM Santosh P K <
>>>> [e-mail]> wrote:
>>>>
>>>>> Dinesh,
>>>>>      Please see my inline comments [SPK]
>>>>>
>>>>>>
>>>>>> - In section 3, there's a sentence that is: "BFD packets intended for
>>>>>> a Hypervisor VTEP MUST NOT..". I recommend getting rid of the word
>>>>>> "Hypervisor" ashe logic applies to any VTEP.
>>>>>>
>>>>>> [SPK] Thanks for comments. We will change this.
>>>>>
>>>>>
>>>>>> - You already explained the precedence of the use of 127/8 address in
>>>>>> the inner header in MPLS. I have no specific comments in that area. I have
>>>>>> only two questions:
>>>>>>    - Has anybody verified that the use of 127/8 address (and the
>>>>>> right MAC) works with existing implementations, including the silicon ones?
>>>>>> If this doesn't work there, is it worth adding the possibilit y of another
>>>>>> address, one that is owned by the VTEP node?
>>>>>>
>>>>>    - Do we know if Firewalls stop such VXLAN packets? I ask this
>>>>>> because VXLAN has an IP header and I don't know if firewalls stop packets
>>>>>> with 127/8 in the inner header. If not, is it worth adding a sentence to
>>>>>> say that firewalls  allow such packets? The use of a non-127/8 address may
>>>>>> alleviate this case as well.
>>>>>>
>>>>>
>>>>> [SPK] I think we may need to add the text about firewall as some
>>>>> checks in firewall will be there if they are not already using MPLS OAM
>>>>> which has inner IP header with 127/8 address range.
>>>>>
>>>>>
>>>>>>
>>>>>> The rest of the draft looks good to me,
>>>>>>
>>>>>> Dinesh
>>>>>>
>>>>>> On Wed, Oct 23, 2019 at 7:58 AM, Greg Mirsky <[e-mail]>
>>>>>> wrote:
>>>>>>
>>>>>> Hi Dinesh,
>>>>>> I greatly appreciate your comments. Please heave a look at the
>>>>>> attached copy of the working version and its diff to -07 (latest in the
>>>>>> datatracker).
>>>>>>
>>>>>> Regards,
>>>>>> Greg
>>>>>>
>>>>>> On Tue, Oct 22, 2019 at 9:52 PM Dinesh Dutt <[e-mail]> wrote:
>>>>>>
>>>>>>> I have the same feeling as Anoop. Greg, can you please point me to
>>>>>>> the latest draft so that I can quickly glance through it to be doubly sure,
>>>>>>>
>>>>>>> Dinesh
>>>>>>>
>>>>>>> On Wed, Oct 23, 2019 at 4:35 AM, Anoop Ghanwani <
>>>>>>> [e-mail]> wrote:
>>>>>>>
>>>>>>> Greg,
>>>>>>>
>>>>>>> I think the draft is fine as is.
>>>>>>>
>>>>>>> I discussion with Xiao Min was about #3 and I see that as
>>>>>>> unnecessary until we have a draft that explains why that is needed in the
>>>>>>> context of the NVO3 architecture.
>>>>>>>
>>>>>>> Anoop
>>>>>>>
>>>>>>> On Tue, Oct 22, 2019 at 11:17 AM Greg Mirsky <[e-mail]>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Hi Anoop, et al.,
>>>>>>>> I agree with your understanding of what is being defined in the
>>>>>>>> current version of the BFD over VxLAN specification. But, as I understand,
>>>>>>>> the WG is discussing the scope before the WGLC is closed. I believe there
>>>>>>>> are three options:
>>>>>>>>
>>>>>>>>    1. single BFD session between two VTEPs
>>>>>>>>    2. single BFD session per VNI between two VTEPs
>>>>>>>>    3. multiple BFD sessions per VNI between two VTEPs
>>>>>>>>
>>>>>>>> The current text reflects #2. Is WG accepts this scope? If not,
>>>>>>>> which option WG would accept?
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>> Greg
>>>>>>>>
>>>>>>>> On Tue, Oct 22, 2019 at 2:09 PM Anoop Ghanwani <
>>>>>>>> [e-mail]> wrote:
>>>>>>>>
>>>>>>>>> I concur with Joel's assessment with the following clarifications.
>>>>>>>>>
>>>>>>>>> The current document is already capable of monitoring multiple
>>>>>>>>> VNIs between VTEPs.
>>>>>>>>>
>>>>>>>>> The issue under discussion was how do we use BFD to monitor
>>>>>>>>> multiple VAPs that use the same VNI between a pair of VTEPs.  The use case
>>>>>>>>> for this is not clear to me, as from my understanding, we cannot have a
>>>>>>>>> situation with multiple VAPs using the same VNI--there is 1:1 mapping
>>>>>>>>> between VAP and VNI.
>>>>>>>>>
>>>>>>>>> Anoop
>>>>>>>>>
>>>>>>>>> On Tue, Oct 22, 2019 at 6:06 AM Joel M. Halpern <
>>>>>>>>> [e-mail]> wrote:
>>>>>>>>>
>>>>>>>>>>  From what I can tell, there are two separate problems.
>>>>>>>>>> The document we have is a VTEP-VTEP monitoring document.  There
>>>>>>>>>> is no
>>>>>>>>>> need for that document to handle the multiple VNI case.
>>>>>>>>>> If folks want a protocol for doing BFD monitoring of things
>>>>>>>>>> behind the
>>>>>>>>>> VTEPs (multiple VNIs), then do that as a separate document.   The
>>>>>>>>>> encoding will be a tenant encoding, and thus sesparate from what
>>>>>>>>>> is
>>>>>>>>>> defined in this document.
>>>>>>>>>>
>>>>>>>>>> Yours,
>>>>>>>>>> Joel
>>>>>>>>>>
>>>>>>>>>> On 10/21/2019 5:07 PM, Jeffrey Haas wrote:
>>>>>>>>>> > Santosh and others,
>>>>>>>>>> >
>>>>>>>>>> > On Thu, Oct 03, 2019 at 07:50:20PM +0530, Santosh P K wrote:
>>>>>>>>>> >>     Thanks for your explanation. This helps a lot. I would
>>>>>>>>>> wait for more
>>>>>>>>>> >> comments from others to see if this what we need in this draft
>>>>>>>>>> to be
>>>>>>>>>> >> supported based on that we can provide appropriate sections in
>>>>>>>>>> the draft.
>>>>>>>>>> >
>>>>>>>>>> > The threads on the list have spidered to the point where it is
>>>>>>>>>> challenging
>>>>>>>>>> > to follow what the current status of the draft is, or should
>>>>>>>>>> be.  :-)
>>>>>>>>>> >
>>>>>>>>>> > However, if I've followed things properly, the question below
>>>>>>>>>> is really the
>>>>>>>>>> > hinge point on what our encapsulation for BFD over vxlan should
>>>>>>>>>> look like.
>>>>>>>>>> > Correct?
>>>>>>>>>> >
>>>>>>>>>> > Essentially, do we or do we not require the ability to permit
>>>>>>>>>> multiple BFD
>>>>>>>>>> > sessions between distinct VAPs?
>>>>>>>>>> >
>>>>>>>>>> > If this is so, do we have a sense as to how we should proceed?
>>>>>>>>>> >
>>>>>>>>>> > -- Jeff
>>>>>>>>>> >
>>>>>>>>>> > [context preserved below...]
>>>>>>>>>> >
>>>>>>>>>> >> Santosh P K
>>>>>>>>>> >>
>>>>>>>>>> >> On Wed, Sep 25, 2019 at 8:10 AM <[e-mail]> 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
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
>>>>>>>>>> nvo3 mailing list
>>>>>>>>>> [e-mail]
>>>>>>>>>> https://www.ietf.org/mailman/listinfo/nvo3
>>>>>>>>>>
>>>>>>>>>