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

[Osama Zia <[e-mail]>]

I would ask this question in another way.

 

At what point do we need to make QoS decisions based on VXLAN header? I do
not see any.

 

>From VM to NVE it can be done in IP/Ethernet. From NVE to rest of the
network again it can be based on IP/Ethernet header. I do not see a value of
using VXLAN/Geneve/GUE header bits for QoS

 

From: nvo3 [mailto:[e-mail]] On Behalf Of Benson Schliesser
Sent: Wednesday, November 12, 2014 11:34 AM
To: [e-mail]
Cc: [e-mail]; Dino Farinacci;
[e-mail]
Subject: Re: [nvo3] I-D Action: draft-xia-nvo3-vxlan-qosmarking-01.txt

 

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






 <mailto:[e-mail]> Behcet Sarikaya

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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 <mailto:[e-mail]> Behcet Sarikaya

November 10, 2014 at 5:47 PM

On Mon, Nov 10, 2014 at 9:41 PM, Brian E Carpenter
 <mailto:[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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