From: "Toke Høiland-Jørgensen" <notifications@github.com> To: tohojo/flent <flent@noreply.github.com> Cc: Subscribed <subscribed@noreply.github.com> Subject: [Flent-users] [tohojo/flent] Using irtt for VoIP tests (#119) Date: Wed, 22 Nov 2017 12:09:32 +0000 (UTC) [thread overview] Message-ID: <tohojo/flent/issues/119@github.com> (raw) [-- Attachment #1.1: Type: text/plain, Size: 2230 bytes --] Since we now have support for a nice UDP measurement tool in irtt, and also the ability to do fallback runner selection, we finally have an opportunity to retire D-ITG for VoIP measurements. This issue is a fork of the discussion from the old monster thread in #106 to deal specifically with the VoIP emulation parts. Some comments from that thread: > > On Nov 20, 2017, at 10:44 PM, flent-users <notifications@github.com> wrote: > > > > A goal for me has been to be able to run Opus at 24 bit, 96Khz, with 2.7ms > > sampling latency. > > Actually getting 8 channels of that through a loaded box would be marvelous. > > Sounds like a musician. :) If it were CBR, I don’t know if this is a way to estimate it: > > 2.7ms ~= 370 packets/sec > @128kbps, 56 bytes / packet (44 data + 12 RTP) > @256kbps, 99 bytes / packet (87 data + 12 RTP) > > Just for fun, a ~256 kbps test between two sites, 50km apart, both using p2p WiFi to the Internet. For realtime audio, I guess it’s the maximums that could be the biggest issue. > > ``` > % ./irtt client -i 2.7ms -l 99 -q -d 10s a.b.c.d and > G.711 can be simulated today with `-i 20ms -l 172 -fill rand -fillall`. I do this test pretty often, and I think it would be a good default voip test. The reason for the 172 vs 160 is the addition of a 12 byte RTP header, which is present in the wireshark trace of a SIP G.711 call: > > https://wiki.wireshark.org/SampleCaptures?action=AttachFile&do=get&target=SIP_CALL_RTP_G711 > > GSM is older now and I'm not sure how much it's still used over the Internet, but since it has a payload size of 33 bytes(?), some statistics would have to be sacrificed. I'd give up server received stats and dual timestamps, so `-i 20ms -l 33 -rs none -ts midpoint` is a start. Not sure about additional headers. > > It should possible to simulate Opus in CBR mode in a similar way. But Opus also supports VBR, which would require varying packet sizes, which irtt can't yet do (plus, this would invalidate or at least pollute the IPDV calculation). -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/tohojo/flent/issues/119 [-- Attachment #1.2: Type: text/html, Size: 4305 bytes --] [-- Attachment #2: Type: text/plain, Size: 151 bytes --] _______________________________________________ Flent-users mailing list Flent-users@flent.org http://flent.org/mailman/listinfo/flent-users_flent.org
next reply other threads:[~2017-11-22 12:10 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-11-22 12:09 Toke Høiland-Jørgensen [this message] 2017-11-23 16:48 ` Toke Høiland-Jørgensen
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