Re: [bmwg] Usage of multiple IP address with RFC 2544 / RFC 5180 compliant throughput tests

Hi Lencse,
	My apologies for the long delay in this; I’d been looking for an RFC to see if this was covered, and I can’t find one. However, my thoughts…
	How OpenBSD chooses to handle (or not) the RSS item is an implementation detail; you know it, which is nice, but we can’t know this for every system on the Internet. Using 1 pseudorandom src/dest IP or using <n> of them seems no different than what test ports would generate (albeit in this case, they’re all pseudorandom I suppose). If I’m missing something let me know, but I wonder if, if we’re confident that there might be some exceptions where the system under test in the lab can’t mimic close to production, then we note it in the document and keep moving forward with the work. Thoughts?

Thank you,
Sarah

> On Jun 5, 2023, at 2:12 AM, Lencse Gábor <lencse@hit.bme.hu> wrote:
> 
> Dear All,
> 
> Is there any RFC that describes how to use multiple IP addresses with RFC 2544 / RFC 5180 compliant throughput tests?
> 
> Originally, RFC 2544 used fixed test frame format. Then RFC 4814 specified how to use pseudorandom source and destination port numbers. However, I did not find any guidance, how one should use multiple, pseudorandom source and destination IP addresses. 
> 
> It is an issue, because in some systems, like OpenBSD, one cannot set the Receive-Side Scaling (RSS) to include also the port numbers into the hash tuple for distributing the interrupts of the incoming packets among the CPU cores. Please see this e-mail for the details: https://marc.info/?l=openbsd-misc&m=166581934723445&w=2
> 
> However, when the system is used to forward Internet traffic, then it faces with different source and destination IP addresses. Thus, the laboratory test results will not reflect the results experienced under operational conditions.
> 
> Now I am working on implementing the usage of pseudorandom source and destination IP addresses in siitperf, my stateful and stateless NAT64 tester, which can also be used to benchmark IPv4 or IPv6 routers. My main motivation is to support stateful NAT64 tests with OpenBSD PF, but I also would like to support stateless IPv4 and IPv6 packet forwarding measurements. 
> 
> Regarding the stateless IPv4 tests, I planned this setup:
> 
>     198.18.[2-65534]/16                            198.19.[2-65534]/16
>               \  +--------------------------------------+  /
>                \ |                                      | /
>    +-------------|                Tester                |<------------+
>    |             |                                      |             |
>    |             +--------------------------------------+             |
>    |                                                                  |
>    |             +--------------------------------------+             |
>    |             |                                      |             |
>    +------------>|          DUT: IPv4 router            |-------------+
>                / |                                      | \
>               /  +--------------------------------------+  \
>     198.18.0.1/16                                        198.19.0.1/16
> 
> I am aware that this solution sacrifices the opportunity of testing with 256 destination networks. 
> 
> Any suggestions are welcome!
> 
> Best regards,
> 
> Gábor
> 
> 
> 
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