Re: [nvo3] I-D Action: draft-xia-nvo3-vxlan-qosmarking-01.txt

[Behcet Sarikaya <[e-mail]>]

On Thu, Nov 13, 2014 at 9:06 PM, Erik Nordmark <[e-mail]> wrote:
>
>  On 11/13/14 4:00 PM, Behcet Sarikaya wrote:
>
>
> On Thu, Nov 13, 2014 at 4:47 PM, Benson Schliesser <[e-mail]>
> wrote:
>
>> Hi, Behcet -
>>
>> Stepping back from the conversation about bits... What is the problem
>> that you're trying to solve, Behcet?
>>
>> I see multiple existing QoS mechanisms both in the underlay and in the
>> overlay, and I don't see any QoS gap that needs to be addressed in the
>> overlap encap layer. I believe that my point of view is consistent with the
>> WG consensus at this point.
>>
>>
> I am not familiar with any QoS mechanism that is based on the tenant, i.e
> static mapping.
> Let me know which document discusses it?
>
>
> Google search points me at rfc2983, rfc6040; latter is for ECN.
>
> There might be other RFCs.
>


Sorry for this belated reply.

I agree that there doesn't seem to be another document on tenant-based QoS.
I read RFC 2983, certainly it is not.

This is possibly because multi tenancy is a new concept in IETF introduced
by nvo3.

Brian Carpenter once suggested to discuss this draft in tcpm, maybe this
was the reason?

We are ready to present it in tcpm and discuss this concept with QoS
experts in tcpm.

Having said that I don't take this comment as negative. I think it is a
valid point.

Regards,

Behcet

>
>
>    Erik
>
>
>
> Thx,
>
> Behcet
>
>>  Thanks,
>> -Benson
>>
>>    Dino Farinacci <[e-mail]>
>>  November 13, 2014 at 12:02 PM
>>
>> Sorry there are no EXP bits mentioned in RFC 7348. MPLS is out of scope.
>>
>> EXP is 3 bits long, DSCP is 6 bits and dividing it into two 3 bit
>> pieces, I am not sure if David will like it.
>>
>>
>>  I am referring to user-priority bits below:
>>
>>
>>  Dino
>>
>>     Benson Schliesser <[e-mail]>
>>  November 12, 2014 at 9:34 AM
>>    Hi, Behcet -
>>
>> Perhaps I'm confused about what comment (from Dino) that you are
>> referring to... But in general, I think of it this way:
>>
>> Assuming the encap stack looks something like: IP1 / Eth1 / VXLAN / UDP /
>> IP2 / Eth2  (progressing L->R as inner->outer)
>>
>> Then e.g. tenant VMs can mark the IP1 and Eth1 headers with whatever
>> appropriate markings they desire. The NVE can mark the IP2 and Eth2 headers
>> with whatever appropriate markings.
>>
>> Specifically, one could imagine the NVE copying the IP1 DSCP codepoint
>> into the IP2 header. Alternatively one could imagine the NVE imposing an
>> underlay DSCP in IP2, e.g. to discriminate between tenants. Possibly, one
>> could also imagine some kind of translation policy which maps IP1
>> codepoints into IP2 codepoints. And that's not even considering mechanisms
>> that leverage the Eth headers, use different encap stacks, etc.
>>
>> Cheers,
>> -Benson
>>
>>    Behcet Sarikaya <[e-mail]>
>>  November 12, 2014 at 9:01 AM
>>   Hi Dino,
>>
>> Regarding your comment on copying IP header QoS bits into VXLAN header,
>>
>> note that IP packet is coming from the VMs.
>>
>> Yes for dynamic marking these bits can be copied.
>> However, VMs may not be configured to mark these fields.
>>
>> For static marking these bits can not be used because VMs are not
>> aware of the VNI. So NVE has to do the static marking.
>>
>> Hope this clarifies.
>>
>> Regards,
>>
>> Behcet
>>
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>>    Behcet Sarikaya <[e-mail]>
>>  November 10, 2014 at 5:47 PM
>>
>> On Mon, Nov 10, 2014 at 9:41 PM, Brian E Carpenter<[e-mail]> <[e-mail]> wrote:
>>
>>  [resend with corrected address, sorry]
>>
>> Hi,
>>
>>
>>   The first three bits (bits 5-7) are precedence bits. They are
>>  assigned according to [RFC0791]. Precedence values '110' and '111'
>>  are selected for routing traffic.
>>
>>  The last three bits (bits 8-10) are class selector bits. Thet are
>>  assigned as follows:
>>
>> 001 - BK or background traffic
>>
>>  ...
>>
>>  As can be seen the markings are the same as in IEEE 802.1p...
>>
>>  This is not in any way compatible with RFC 2474, which also made the
>> relevant part of RFC 791 obsolete.
>>
>> If you want to be compatible with RFC 2474 you should not specify the
>> bits at all - just say that they are exactly as defined in RFC 2474
>> and the various PHB definitions that have been published.
>>
>>  I think that diffserv is less relevant in the context of VXLAN.
>>
>>
>>   If you
>> want to be compatible with IEEE 802.1p that is a different matter,
>>
>>  Yes this is more relevant for VXLAN.
>>
>>
>>  but you cannot mix the two up in this way.
>>
>>  I now understand that we confused the two very different things.
>>
>> Regards,
>>
>> Behcet
>>
>>      Brian
>>
>>
>>
>>
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