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

[Benson Schliesser <[e-mail]>]

Hi, Behcet -

Quoting from my previous message: "one could imagine the NVE imposing an 
underlay DSCP in IP2, e.g. to discriminate between tenants."

This seems so obvious to me that I doubt anybody has bothered to write 
it down...

It does seem like we should document a mechanism for configuration of 
the NVE's QoS behavior. (E.g. as part of the NVO3 control plane and/or 
in a YANG model for NVE management) But that's a different topic.

So, back to my question: Is there actually a problem that you trying to 
solve that cannot be solved with the existing mechanisms?

If so, then I will reconsider my beliefs about WG consensus. But if not, 
then I don't see why we're having this conversation.

Thanks,
-Benson


> Behcet Sarikaya <mailto:[e-mail]>
> November 13, 2014 at 4:00 PM
>
> On Thu, Nov 13, 2014 at 4:47 PM, Benson Schliesser 
> <[e-mail] <mailto:[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?
> Thx,
> Behcet
>
>     Thanks,
>     -Benson
>
>>     Dino Farinacci <mailto:[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 <mailto:[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 <mailto:[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
>>
>>     _______________________________________________
>>     nvo3 mailing list
>>     [e-mail] <mailto:[e-mail]>
>>     https://www.ietf.org/mailman/listinfo/nvo3
>>     Behcet Sarikaya <mailto:[e-mail]>
>>     November 10, 2014 at 5:47 PM
>>     On Mon, Nov 10, 2014 at 9:41 PM, Brian E Carpenter
>>     <[e-mail]>  <mailto:[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
>>>
>>>
>>>
>>     _______________________________________________
>>     nvo3 mailing list
>>     [e-mail]  <mailto:[e-mail]>
>>     https://www.ietf.org/mailman/listinfo/nvo3
>
>
> Benson Schliesser <mailto:[e-mail]>
> November 13, 2014 at 12:47 PM
> 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.
>
> Thanks,
> -Benson
>
> Dino Farinacci <mailto:[e-mail]>
> November 12, 2014 at 8:06 PM
>
> Exactly. Thanks Benson.
>
> Dino
> Benson Schliesser <mailto:[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 <mailto:[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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