[dpdk-dev] Is it possible to get symmetric hash from RSS for a given flow

Daniel Kan dan at nyansa.com
Fri Feb 28 06:34:02 CET 2014

The symmetric RSK for 5-tuple is a generalized case for 2-tuple src ip/dst ip. You can use the same RSK to get the symmetric load balancing. 


On Feb 27, 2014, at 5:08 PM, Stefan Baranoff <sbaranoff at gmail.com> wrote:

> Has anyone already applied this logic to IP only load balancing to get SRC/DST and DST/SRC on the same queue and come up with an RSK value? If not I'll spend some time with a calculator and see if I can get one.
> Thanks,
> Stefan
> Sent from my smart phone; people don't make typos, Swype does!
> On Feb 27, 2014 8:04 PM, "Daniel Kan" <dan at nyansa.com> wrote:
> Thanks, Sangjin. This is exactly i’m looking for. Sorry, I should’ve googled it first. It’s good to know that hash key of repetitive 0x6d5a still yields good load balancing results.
> Dan
> On Feb 27, 2014, at 4:24 PM, Sangjin Han <sangjin at eecs.berkeley.edu> wrote:
> > Hi,
> >
> > This is exactly what you want:
> > http://www.ndsl.kaist.edu/~shinae/papers/TR-symRSS.pdf
> >
> > Sangjin
> >
> > On Thu, Feb 27, 2014 at 4:22 PM, Daniel Kan <dan at nyansa.com> wrote:
> >> Hi,
> >> It appears that the hash computed from RSS is unidirectional. Hence, for a 5-tuple flow, packet in one direction can be routed to a queue that may be different than packet in the other direction. I'm wondering if there is a configuration or mechanism to get a symmetric hash so that all packets for a given flow will be in the same queue. Thanks in advance.
> >>
> >> Dan

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