Bob, Good question. So here is a typical scenario. We have a VOIP server sitting inside of a customer's data center behind a firewall (e.g. Sonicwall, PfSense, Palo Alto, etc.). The phone server is sitting on a VLAN inside the customer's network and has a 1Gb NIC. The customer (most of ours are very large) has a 200Mb Internet pipe from an ISP. Depending on the concurrent call volume we ask the customer to do traffic shaping and guarantee us 10Mb of the 200Mb pipe. They call after working fine for 2 years and complain that they can't hear outside callers (UDP traffic from the carrier into the VOIP server is being disrupted). We will run iperf tests from an external location (like on our VM setup at our office, or a VM we have on AWS) and start shooting UDP packets in (usually starting at 1Mb with a small datagram and working our way up to the 10Mb limit). Most of the time we start seeing issues with dropped packets at 3Mb/s. This then forces us to look at the Firewall and see if it is overwhelmed doing the shaping. If not then we setup a "triangulation" where we do iperf tests with 2 separate external sources and see the times when both pipes show dropped packets. If we see consistent drops from 2 separate legs this invariable points to an upstream problem at the ISP.
Hope that helps, Craig Reeves "Bridging Communications" 3520 Lorna Ridge Drive Hoover, AL 35216 v.(205) 829-1800 f. (205) 536-6333 c. (205) 332-5916 On Tue, Dec 1, 2020 at 2:08 PM Bob McMahon <bob.mcma...@broadcom.com> wrote: > For UDP, are you expecting the sweep applies both to client and server at > the same time? I guess I'm confused about UDP read size rate limiting. If > the client applies 100m and the server is read limited per a sweep there is > going to be drops. UDP doesn't flow control the client. > > Bob > > On Tue, Dec 1, 2020 at 11:42 AM Craig Reeves <craigree...@ambit-llc.com> > wrote: > >> Yes, but the percentage of drops is fairly low in a clean network pipe. >> >> Craig Reeves >> >> "Bridging Communications" >> 3520 Lorna Ridge Drive >> Hoover, AL 35216 >> v.(205) 829-1800 >> f. (205) 536-6333 >> c. (205) 332-5916 >> >> >> On Tue, Dec 1, 2020 at 1:39 PM Bob McMahon <bob.mcma...@broadcom.com> >> wrote: >> >>> Ok, read side limiting would trigger source flow control for TCP and >>> cause drops per UDP. Is that what you'd expect? >>> >>> Bob >>> >>> On Tue, Dec 1, 2020 at 11:36 AM Craig Reeves <craigree...@ambit-llc.com> >>> wrote: >>> >>>> Bob, >>>> >>>> Yes, we would need the Read side as well. Sometimes we see packets >>>> drop from a single direction (that is actually very common). Technically >>>> we could just flip the roles of the 2 ends so it isn't critical. >>>> >>>> Craig Reeves >>>> >>>> "Bridging Communications" >>>> 3520 Lorna Ridge Drive >>>> Hoover, AL 35216 >>>> v.(205) 829-1800 >>>> f. (205) 536-6333 >>>> c. (205) 332-5916 >>>> >>>> >>>> On Tue, Dec 1, 2020 at 1:32 PM Bob McMahon <bob.mcma...@broadcom.com> >>>> wrote: >>>> >>>>> Also, this would only be on the client. Iperf 2.0.14 supports both >>>>> write and read rate limiting via -b on the server as well as client. >>>>> Sweeps wouldn't be supported by the server (or on the read side.) >>>>> >>>>> Any issue with that, or, is there a read size need as well? >>>>> >>>>> Bob >>>>> >>>>> On Tue, Dec 1, 2020 at 11:29 AM Craig Reeves < >>>>> craigree...@ambit-llc.com> wrote: >>>>> >>>>>> Bob, >>>>>> >>>>>> Thanks, we'd be more than happy to test it out. Just let me know and >>>>>> I'll get my engineering group to check it out. >>>>>> >>>>>> Craig Reeves >>>>>> >>>>>> "Bridging Communications" >>>>>> 3520 Lorna Ridge Drive >>>>>> Hoover, AL 35216 >>>>>> v.(205) 829-1800 >>>>>> f. (205) 536-6333 >>>>>> c. (205) 332-5916 >>>>>> >>>>>> >>>>>> On Tue, Dec 1, 2020 at 1:21 PM Bob McMahon <bob.mcma...@broadcom.com> >>>>>> wrote: >>>>>> >>>>>>> Hi Craig, >>>>>>> >>>>>>> Any reason you need iperf 3 for this and can't use iperf 2.0.14? >>>>>>> >>>>>>> We are in the process of early field test for iperf 2.0.14. >>>>>>> <https://sourceforge.net/projects/iperf2/> This is probably an >>>>>>> experimental feature that could be added last minute. We'd need you to >>>>>>> test if willing. Our goal is to release 2.0.14 early 2021. >>>>>>> >>>>>>> We're out of short options and would need to use long options. Maybe >>>>>>> something like >>>>>>> >>>>>>> --sweep-range=1m,100m, 1m (start, final, step size) defaults to >>>>>>> 1m,10m,1m with just --sweep-range >>>>>>> --sweep-steptime 1.5 (units of seconds) defaults to 1 second if >>>>>>> --sweep-range and no --sweep-steptime >>>>>>> >>>>>>> Note that --sweep-range has optional arguments (per the =) and >>>>>>> sweep-steptime has a mandatory argument (if used.) >>>>>>> >>>>>>> All, do comment on more intuitive command line options. >>>>>>> >>>>>>> Bob >>>>>>> >>>>>>> >>>>>>> >>>>>>> Bob >>>>>>> >>>>>>> On Tue, Dec 1, 2020 at 8:12 AM Craig Reeves < >>>>>>> craigree...@ambit-llc.com> wrote: >>>>>>> >>>>>>>> First, many thanks for putting this tool together and sharing it. >>>>>>>> It has proved invaluable over the years when dealing with ISPs. >>>>>>>> >>>>>>>> That being said, we regularly encounter ISPs that don't think their >>>>>>>> network has issues. Most of the time we can pinpoint to a switch or >>>>>>>> connection that is over saturated. >>>>>>>> >>>>>>>> I would love to see a feature that allowed us to set a starting >>>>>>>> throughput, incremental step up/down throughput, and interval. This >>>>>>>> would >>>>>>>> help find the point at which issues begin. Here is the idea: >>>>>>>> >>>>>>>> iperf3 -c 192.168.1.100 -bt 1M -et 10M -st 10s -t 100 -u >>>>>>>> >>>>>>>> -bt = beginning throughput >>>>>>>> -et = ending throughput >>>>>>>> -st = step up/down time >>>>>>>> >>>>>>>> The thinking is that iperf3 would start a test (UDP or TCP) at >>>>>>>> 1Mb/s throughput, and then ramp up in 1Mb/s steps ever 10 seconds. >>>>>>>> >>>>>>>> This eliminates the need to do individual runs with different >>>>>>>> settings. >>>>>>>> >>>>>>>> Thank you, >>>>>>>> >>>>>>>> Craig Reeves >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> Iperf-users mailing list >>>>>>>> Iperf-users@lists.sourceforge.net >>>>>>>> https://lists.sourceforge.net/lists/listinfo/iperf-users >>>>>>>> >>>>>>>
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