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

[Behcet Sarikaya <[e-mail]>]

On Thu, Nov 13, 2014 at 8:05 PM, Osama Bin Zia <[e-mail]> wrote:

>  So if I remember correctly you already agreed to my earlier email that
> there is no point where we will need to use QoS based encapsulation header.
>
> No, it was about where QoS coding would be made, so I had agreed that UDP
header or the flag bits are probably not the right place. I had agreed with
you that outer Ethernet header or IP2 header bits need to be used.


> Now the question is why do we need it in there if we will not use it?
>
> See above.


> --- Original Message ---
>
> From: "Behcet Sarikaya" <[e-mail]>
> Sent: November 13, 2014 4:00 PM
> To: "Benson Schliesser" <[e-mail]>
> Cc: [e-mail], "Dino Farinacci" <[e-mail]>,
> [e-mail]
> Subject: Re: [nvo3] I-D Action: draft-xia-nvo3-vxlan-qosmarking-01.txt
>
>
> 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?
>
> 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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