On 4/7/15 12:02 AM, Lizhong Jin wrote:
Hi Erik,
Thanks for the draft. I suggest to add one consideration: the generation of
entropy value.
1. When the node receive an UDP/TCP packet from the tenant, then entropy
value could be a hash value of 5-tuple.
2. When the node receive an IP packet from the tenant, then entropy value
could be a hash value of 2-tuple.
3. When the node receive an Ethernet packet from the tenant, then entropy
value could be a hash value of MAC address.
4. When the node receive an IP fragmented packet from the tenant, the first
fragment is UDP/TCP, and entropy will be from 5-tuple. But the second and
subsequent segments will generate entropy from 2-tuple, which will have
different entropy value with the first segment. The issue could not be
resolved currently if NVE is separated from tenant into two physical
devices.
Lizhong,
I've been assuming that the above issues are well-known, since entropy
is generated and used locally for LAGs and L3 ECMP even when there is no
encaps. Taking that entropy result and sticking it in a field in the
packet doesn't add to the issues AFAICT.
I don't know if there is a document we can reference that states the
above general considerations for flow entropy/hashing. Has anybody seen
such a document? If so we can definitely reference it.
For section 18.1.1, I suggest RFS should be analyzed. E.g., if NIC want to
do flow steering based on the inner header information, then it could use
entropy value instead of the inner header information.
Did you mean Receive Side Scaling (RSS)? That is mentioned in the
document - section 18.1.1 . Perhaps the RSS text can be improved.
Receive Flow Scaling is the name of a Linux software technique to take
into account the CPU on which the application is running, which is
different.
Thanks,
Erik
Regards
Lizhong
-----Original Message-----
From: Erik Nordmark [mailto:[email protected]]
Sent: 2015年3月26日 5:01
To: [email protected]
Subject: [nvo3] Encapsulation considerations
I presented part of this at the most recent NVO3 interim meeting.The full
12
areas of considerations where presented at RTGWG earlier this week.
The draft is
http://datatracker.ietf.org/doc/draft-rtg-dt-encap/
and the slides are at
http://www.ietf.org/proceedings/92/slides/slides-92-rtgwg-8.pdf
There is probably additional things in there to consider for NVO3, and
advice
that can be reused to make it easier to move NVO3 forward.
Regards,
Erik
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