iperf 2 supports OWD in multiple forms.
A raspberry pi 5 has a realtime clock and hardware PTP and gpio PPS. The
retail cost for a pi5 with GPS atomic clock and active fan is less than
$150
[rjmcmahon@fedora iperf2-code]$ src/iperf -c 192.168.1.35 --bounceback
--trip-times --bounceback-period 0 -i 1 -t 4
------------------------------------------------------------
Client connecting to 192.168.1.35, TCP port 5001 with pid 48142 (1/0
flows/load)
Bounceback test (req/reply size = 100 Byte/ 100 Byte) (server hold req=0
usecs & tcp_quickack)
TCP congestion control using cubic
TOS set to 0x0 and nodelay (Nagle off)
TCP window size: 85.0 KByte (default)
Event based writes (pending queue watermark at 16384 bytes)
------------------------------------------------------------
[ 1] local 192.168.1.103%enp4s0 port 50558 connected with 192.168.1.35
port 5001 (prefetch=16384) (bb w/quickack req/reply/hold=100/100/0)
(trip-times) (sock=3) (icwnd/mss/irtt=14/1448/541) (ct=0.59 ms) on
2023-12-07 22:01:39.240 (PST)
[ ID] Interval Transfer Bandwidth BB
cnt=avg/min/max/stdev Rtry Cwnd/RTT RPS(avg)
[ 1] 0.00-1.00 sec 739 KBytes 6.05 Mbits/sec
7566=0.130/0.099/0.627/0.007 ms 0 14K/115 us 7666 rps
[ 1] 0.00-1.00 sec OWD (ms) Cnt=7566 TX=0.072/0.038/0.163/0.002
RX=0.058/0.047/0.156/0.004 Asymmetry=0.015/0.001/0.103/0.004
[ 1] 1.00-2.00 sec 745 KBytes 6.10 Mbits/sec
7630=0.130/0.082/0.422/0.005 ms 0 14K/114 us 7722 rps
[ 1] 1.00-2.00 sec OWD (ms) Cnt=7630 TX=0.073/0.027/0.364/0.004
RX=0.057/0.048/0.097/0.003 Asymmetry=0.016/0.000/0.306/0.005
[ 1] 2.00-3.00 sec 749 KBytes 6.14 Mbits/sec
7671=0.129/0.085/0.252/0.004 ms 0 14K/113 us 7756 rps
[ 1] 2.00-3.00 sec OWD (ms) Cnt=7671 TX=0.073/0.031/0.193/0.003
RX=0.056/0.047/0.102/0.003 Asymmetry=0.017/0.000/0.134/0.004
[ 1] 3.00-4.00 sec 737 KBytes 6.04 Mbits/sec
7546=0.131/0.085/0.290/0.004 ms 0 14K/115 us 7629 rps
[ 1] 3.00-4.00 sec OWD (ms) Cnt=7546 TX=0.073/0.030/0.231/0.003
RX=0.058/0.047/0.105/0.003 Asymmetry=0.015/0.000/0.172/0.004
[ 1] 0.00-4.00 sec 2.90 MBytes 6.08 Mbits/sec
30414=0.130/0.082/0.627/0.005 ms 0 14K/376 us 7693 rps
[ 1] 0.00-4.00 sec OWD (ms) Cnt=30414 TX=0.073/0.027/0.364/0.003
RX=0.057/0.047/0.156/0.004 Asymmetry=0.016/0.000/0.306/0.004
[ 1] 0.00-4.00 sec OWD-TX(f)-PDF:
bin(w=100us):cnt(30414)=1:30393,2:19,3:1,4:1
(5.00/95.00/99.7%=1/1/1,Outliers=0,obl/obu=0/0)
[ 1] 0.00-4.00 sec OWD-RX(f)-PDF: bin(w=100us):cnt(30414)=1:30400,2:14
(5.00/95.00/99.7%=1/1/1,Outliers=0,obl/obu=0/0)
[ 1] 0.00-4.00 sec BB8(f)-PDF:
bin(w=100us):cnt(30414)=1:6,2:30392,3:14,5:1,7:1
(5.00/95.00/99.7%=2/2/2,Outliers=16,obl/obu=0/0)
Bob
On Dec 6, 2023, at 22:46, Sauli Kiviranta via Nnagain
<nnag...@lists.bufferbloat.net> wrote:
What would be a comprehensive measurement? Should cover all/most
relevant areas?
It’s easy to specify a suite of measurements which is too heavy to be
easily implemented or supported on the network. Also, as you point
out, many things can be derived from raw data, so don’t necessarily
require additional specific measurements.
Payload Size: The size of data being transmitted.
Event Rate: The frequency at which payloads are transmitted.
Bitrate: The combination of rate and size transferred in a given test.
Throughput: The data transfer capability achieved on the test path.
All of that can probably be derived from sufficiently finely-grained
TCP data. i.e. if you had a PCAP of a TCP flow that constituted the
measurement, you’d be able to derive all of the above.
Bandwidth: The data transfer capacity available on the test path.
Presumably the goal of a TCP transaction measurement would be to
enable this calculation.
Transfer Efficiency: The ratio of useful payload data to the overhead
data.
This is a how-its-used rather than a property-of-the-network. If
there are network-inherent overheads, they’re likely to be not
directly visible to endpoints, only inferable, and might require
external knowledge of the network. So, I’d put this out-of-scope.
Round-Trip Time (RTT): The ping delay time to the target server and
back.
RTT Jitter: The variation in the delay of round-trip time.
Latency: The transmission delay time to the target server and back.
Latency Jitter: The variation in delay of latency.
RTT is measurable. If Latency is RTT minus processing delay on the
remote end, I’m not sure it’s really measurable, per se, without the
remote end being able to accurately clock itself, or an independent
vantage point adjacent to the remote end. This is the
old[rjmcmahon@fedora iperf2-code]$ src/iperf -c 192.168.1.35
--bounceback --trip-times --bounceback-period 0 -i 1 -t 4
------------------------------------------------------------
Client connecting to 192.168.1.35, TCP port 5001 with pid 46358 (1/0
flows/load)
Bounceback test (req/reply size = 100 Byte/ 100 Byte) (server hold req=0
usecs & tcp_quickack)
TCP congestion control using cubic
TOS set to 0x0 and nodelay (Nagle off)
TCP window size: 85.0 KByte (default)
Event based writes (pending queue watermark at 16384 bytes)
------------------------------------------------------------
[ 1] local 192.168.1.103%enp4s0 port 60788 connected with 192.168.1.35
port 5001 (prefetch=16384) (bb w/quickack req/reply/hold=100/100/0)
(trip-times) (sock=3) (icwnd/mss/irtt=14/1448/168) (ct=0.23 ms) on
2023-12-07 21:21:31.417 (PST)
[ ID] Interval Transfer Bandwidth BB
cnt=avg/min/max/stdev Rtry Cwnd/RTT RPS(avg)
[ 1] 0.00-1.00 sec 745 KBytes 6.10 Mbits/sec
7631=0.129/0.096/0.637/0.007 ms 0 14K/114 us 7733 rps
[ 1] 0.00-1.00 sec OWD (ms) Cnt=7631 TX=0.068/0.034/0.191/0.003
RX=0.061/0.049/0.118/0.004 Asymmetry=0.009/0.000/0.130/0.004
** reset
[ 1] 1.00-2.00 sec 751 KBytes 6.15 Mbits/sec
7689=0.129/0.092/0.350/0.005 ms 0 14K/115 us 7782 rps
[ 1] 1.00-2.00 sec OWD (ms) Cnt=7689 TX=0.069/0.030/0.288/0.004
RX=0.060/0.052/0.116/0.003 Asymmetry=0.009/0.000/0.227/0.004
** reset
[ 1] 2.00-3.00 sec 748 KBytes 6.13 Mbits/sec
7664=0.129/0.085/0.378/0.004 ms 0 14K/115 us 7751 rps
[ 1] 2.00-3.00 sec OWD (ms) Cnt=7664 TX=0.069/0.025/0.313/0.003
RX=0.060/0.053/0.098/0.002 Asymmetry=0.008/0.000/0.248/0.004
** reset
[ 1] 3.00-4.00 sec 752 KBytes 6.16 Mbits/sec
7698=0.128/0.087/0.322/0.004 ms 0 14K/114 us 7787 rps
[ 1] 3.00-4.00 sec OWD (ms) Cnt=7698 TX=0.068/0.023/0.257/0.003
RX=0.060/0.052/0.091/0.002 Asymmetry=0.009/0.000/0.192/0.004
** reset
** reset
[ 1] 0.00-4.00 sec 2.93 MBytes 6.13 Mbits/sec
30683=0.129/0.085/0.637/0.005 ms 0 14K/408 us 7763 rps
[ 1] 0.00-4.00 sec OWD (ms) Cnt=30683 TX=0.068/0.023/0.313/0.003
RX=0.060/0.049/0.118/0.003 Asymmetry=0.009/0.000/0.248/0.004
[ 1] 0.00-4.00 sec OWD-TX(f)-PDF:
bin(w=100us):cnt(30683)=1:30663,2:17,3:2,4:1
(5.00/95.00/99.7%=1/1/1,Outliers=0,obl/obu=0/0)
[ 1] 0.00-4.00 sec OWD-RX(f)-PDF: bin(w=100us):cnt(30683)=1:30669,2:14
(5.00/95.00/99.7%=1/1/1,Outliers=0,obl/obu=0/0)
[ 1] 0.00-4.00 sec BB8(f)-PDF:
bin(w=100us):cnt(30683)=1:7,2:30663,3:9,4:3,7:1
(5.00/95.00/99.7%=2/2/2,Outliers=13,obl/obu=0/0)
[rjmcmahon@fedora iperf2-code]$ emacs src/Reporter.c
[rjmcmahon@fedora iperf2-code]$ make -j
make all-recursive
make[1]: Entering directory '/home/rjmcmahon/Code/csv/iperf2-code'
Making all in compat
make[2]: Entering directory
'/home/rjmcmahon/Code/csv/iperf2-code/compat'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/home/rjmcmahon/Code/csv/iperf2-code/compat'
Making all in doc
make[2]: Entering directory '/home/rjmcmahon/Code/csv/iperf2-code/doc'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/home/rjmcmahon/Code/csv/iperf2-code/doc'
Making all in include
make[2]: Entering directory
'/home/rjmcmahon/Code/csv/iperf2-code/include'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory
'/home/rjmcmahon/Code/csv/iperf2-code/include'
Making all in src
make[2]: Entering directory '/home/rjmcmahon/Code/csv/iperf2-code/src'
gcc -DHAVE_CONFIG_H -I. -I.. -I../include -I../include -Wall -O2 -O2
-MT Reporter.o -MD -MP -MF .deps/Reporter.Tpo -c -o Reporter.o
Reporter.c
mv -f .deps/Reporter.Tpo .deps/Reporter.Po
g++ -Wall -O2 -O2 -O2 -pthread -DHAVE_CONFIG_H -o iperf Client.o
Extractor.o isochronous.o Launch.o active_hosts.o Listener.o Locale.o
PerfSocket.o Reporter.o Reports.o ReportOutputs.o Server.o Settings.o
SocketAddr.o gnu_getopt.o gnu_getopt_long.o histogram.o main.o service.o
socket_io.o stdio.o packet_ring.o tcp_window_size.o pdfs.o dscp.o
iperf_formattime.o iperf_multicast_api.o checksums.o
../compat/libcompat.a -lrt
make[2]: Leaving directory '/home/rjmcmahon/Code/csv/iperf2-code/src'
Making all in man
make[2]: Entering directory '/home/rjmcmahon/Code/csv/iperf2-code/man'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/home/rjmcmahon/Code/csv/iperf2-code/man'
Making all in flows
make[2]: Entering directory '/home/rjmcmahon/Code/csv/iperf2-code/flows'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/home/rjmcmahon/Code/csv/iperf2-code/flows'
make[2]: Entering directory '/home/rjmcmahon/Code/csv/iperf2-code'
make[2]: Leaving directory '/home/rjmcmahon/Code/csv/iperf2-code'
make[1]: Leaving directory '/home/rjmcmahon/Code/csv/iperf2-code'
[rjmcmahon@fedora iperf2-code]$ src/iperf -c 192.168.1.35 --bounceback
--trip-times --bounceback-period 0 -i 1 -t 4
------------------------------------------------------------
Client connecting to 192.168.1.35, TCP port 5001 with pid 46427 (1/0
flows/load)
Bounceback test (req/reply size = 100 Byte/ 100 Byte) (server hold req=0
usecs & tcp_quickack)
TCP congestion control using cubic
TOS set to 0x0 and nodelay (Nagle off)
TCP window size: 85.0 KByte (default)
Event based writes (pending queue watermark at 16384 bytes)
------------------------------------------------------------
[ 1] local 192.168.1.103%enp4s0 port 37748 connected with 192.168.1.35
port 5001 (prefetch=16384) (bb w/quickack req/reply/hold=100/100/0)
(trip-times) (sock=3) (icwnd/mss/irtt=14/1448/177) (ct=0.23 ms) on
2023-12-07 21:21:46.282 (PST)
[ ID] Interval Transfer Bandwidth BB
cnt=avg/min/max/stdev Rtry Cwnd/RTT RPS(avg)
[ 1] 0.00-1.00 sec 738 KBytes 6.04 Mbits/sec
7552=0.131/0.115/0.642/0.007 ms 0 14K/115 us 7652 rps
[ 1] 0.00-1.00 sec OWD (ms) Cnt=7552 TX=0.070/0.053/0.184/0.002
RX=0.061/0.048/0.113/0.004 Asymmetry=0.009/0.000/0.116/0.004
[ 1] 1.00-2.00 sec 739 KBytes 6.05 Mbits/sec
7568=0.131/0.078/0.362/0.004 ms 0 14K/114 us 7657 rps
[ 1] 1.00-2.00 sec OWD (ms) Cnt=7568 TX=0.070/0.020/0.298/0.003
RX=0.061/0.051/0.097/0.003 Asymmetry=0.009/0.000/0.235/0.004
[ 1] 2.00-3.00 sec 739 KBytes 6.06 Mbits/sec
7571=0.131/0.089/0.279/0.005 ms 0 14K/115 us 7660 rps
[ 1] 2.00-3.00 sec OWD (ms) Cnt=7571 TX=0.070/0.025/0.215/0.003
RX=0.060/0.051/0.181/0.004 Asymmetry=0.010/0.000/0.151/0.004
[ 1] 3.00-4.00 sec 751 KBytes 6.15 Mbits/sec
7693=0.129/0.090/0.284/0.004 ms 0 14K/115 us 7780 rps
[ 1] 3.00-4.00 sec OWD (ms) Cnt=7693 TX=0.070/0.032/0.223/0.004
RX=0.058/0.050/0.091/0.002 Asymmetry=0.013/0.000/0.162/0.004
[ 1] 0.00-4.00 sec 2.90 MBytes 6.07 Mbits/sec
30385=0.130/0.078/0.642/0.005 ms 0 14K/404 us 7687 rps
[ 1] 0.00-4.00 sec OWD (ms) Cnt=30385 TX=0.070/0.020/0.298/0.003
RX=0.060/0.048/0.181/0.004 Asymmetry=0.010/0.000/0.235/0.004
[ 1] 0.00-4.00 sec OWD-TX(f)-PDF:
bin(w=100us):cnt(30385)=1:30366,2:16,3:3
(5.00/95.00/99.7%=1/1/1,Outliers=0,obl/obu=0/0)
[ 1] 0.00-4.00 sec OWD-RX(f)-PDF: bin(w=100us):cnt(30385)=1:30360,2:25
(5.00/95.00/99.7%=1/1/1,Outliers=0,obl/obu=0/0)
[ 1] 0.00-4.00 sec BB8(f)-PDF:
bin(w=100us):cnt(30385)=1:4,2:30366,3:13,4:1,7:1
(5.00/95.00/99.7%=2/2/2,Outliers=15,obl/obu=0/0)
[rjmcmahon@fedora iperf2-code]$ git diff
one-way-delay measurement problem in different guise, I think.
Anyway, I think RTT is easy and necessary, and I think latency is
difficult and probably an anchor not worth attaching to anything we
want to see done in the near term. Latency jitter likewise.
Bit Error Rate: The corrupted bits as a percentage of the total
transmitted data.
This seems like it can be derived from a PCAP, but doesn’t really
constitute an independent measurement.
Packet Loss: The percentage of packets lost that needed to be
recovered.
Yep.
Energy Efficiency: The amount of energy consumed to achieve the test
result.
Not measurable.
Did I overlook something?
Out-of-order delivery is the fourth classical quality criterion.
There are folks who argue that it doesn’t matter anymore, and others
who (more compellingly, to my mind) argue that it’s at least as
relevant as ever.
Thus, for an actual measurement suite:
- A TCP transaction
…from which we can observe:
- Loss
- RTT (which I’ll just call “Latency” because that’s what people have
called it in the past)
- out-of-order delivery
- Jitter in the above three, if the transaction continues long enough
…and we can calculate:
- Goodput
In addition to these, I think it’s necessary to also associate a
traceroute (and, if available and reliable, a reverse-path traceroute)
in order that it be clear what was measured, and a timestamp, and a
digital signature over the whole thing, so we can know who’s attesting
to the measurement.
-Bill
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