[NNagain] CFP march 1 - network measurement conference

rjmcmahon rjmcmahon at rjmcmahon.com
Fri Dec 8 01:03:07 EST 2023


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 at 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 
>> <nnagain at 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 at 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 at fedora iperf2-code]$ emacs src/Reporter.c
[rjmcmahon at 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 at 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 at 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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