ndt-users list created

[Maurice Volaski <>]

> The NDT server puts the interface into promiscuous mode and measures 
> the arrival time of packet-pairs.  The "unknown link type" message 
> indicates that this task is failing.  The typical reason for this is 
> because there are multiple NIC's installed and you are not using the 
> 1st interface in the list.
>
> Run the '/sbin/ifconfig' command and determine the name of the 
> interface you are using (eth0 is the 1st interface).
> Then start the web100srv process with the '-iethx' option (where x 
> is the interface number).  If you are using the ndt start script 
> from the conf directory, then edit this file and add this option to 
> the

Thanks, that fixes the unknown problem, but it still doesn't quite 
report ordinary gigabit, but "2.4 Gbps OC-48" instead. In the 
statistics, the result is more complex, the client report OC-48, the 
server and client "acks" report OC-12 and the server "acks" report 10 
Gig.


WEB100 Enabled Statistics:
Checking for Middleboxes . . . . . . . . . . . . . . . . . .  Done
checking for firewalls . . . . . . . . . . . . . . . . . . .  Done
running 10s outbound test (client-to-server [C2S]) . . . . . 373.36Mb/s
running 10s inbound test (server-to-client [S2C]) . . . . . . 419.60Mb/s

        ------  Client System Details  ------
OS data: Name = Mac OS X, Architecture = i386, Version = 10.4.11
Java data: Vendor = Apple Computer, Inc., Version = 1.5.0_13

        ------  Web100 Detailed Analysis  ------
2.4 Gbps OC-48 link found.
Link set to Full Duplex mode
No network congestion discovered.
Good network cable(s) found
Normal duplex operation found.

Web100 reports the Round trip time = 0.87 msec; the Packet size = 
1448 Bytes; and
No packet loss - but packets arrived out-of-order 4.34% of the time
S2C throughput test: Packet queuing detected: 0.10%
This connection is receiver limited 4.32% of the time.
  Increasing the the client's receive buffer (63.0 KB) will improve 
performance
This connection is sender limited 94.21% of the time.
This connection is network limited 1.47% of the time.

Web100 reports TCP negotiated the optional Performance Settings to:
RFC 2018 Selective Acknowledgment: ON
RFC 896 Nagle Algorithm: ON
RFC 3168 Explicit Congestion Notification: OFF
RFC 1323 Time Stamping: ON
RFC 1323 Window Scaling: OFF

Server 'theradargun.aecom.yu.edu' is not behind a firewall. 
[Connection to the ephemeral port was successful]
Client is probably behind a firewall. [Connection to the ephemeral port 
failed]
Information: Network Middlebox is modifying MSS variable
Server IP addresses are preserved End-to-End
Client IP addresses are preserved End-to-End
-----------

WEB100 Kernel Variables:
Client: localhost/127.0.0.1
CurMSS: 1448
X_Rcvbuf: 33554432
X_Sndbuf: 33554432
AckPktsIn: 74954
AckPktsOut: 0
BytesRetrans: 0
CongAvoid: 0
CongestionOverCount: 0
CongestionSignals: 0
CountRTT: 68278
CurCwnd: 99912
CurRTO: 204
CurRwinRcvd: 65535
CurRwinSent: 6144
CurSsthresh: 2147483647
DSACKDups: 0
DataBytesIn: 0
DataBytesOut: 526888512
DataPktsIn: 0
DataPktsOut: 365616
DupAcksIn: 3255
ECNEnabled: 0
FastRetran: 0
MaxCwnd: 99912
MaxMSS: 1448
MaxRTO: 216
MaxRTT: 92
MaxRwinRcvd: 65535
MaxRwinSent: 6144
MaxSsthresh: 0
MinMSS: 1448
MinRTO: 204
MinRTT: 0
MinRwinRcvd: 8648
MinRwinSent: 5792
NagleEnabled: 1
OtherReductions: 0
PktsIn: 74954
PktsOut: 365616
PktsRetrans: 0
RcvWinScale: 9
SACKEnabled: 3
SACKsRcvd: 0
SendStall: 0
SlowStart: 67
SampleRTT: 0
SmoothedRTT: 4
SndWinScale: 0
SndLimTimeRwin: 432412
SndLimTimeCwnd: 147750
SndLimTimeSender: 9440825
SndLimTransRwin: 8813
SndLimTransCwnd: 11
SndLimTransSender: 8825
SndLimBytesRwin: 215916064
SndLimBytesCwnd: 272960
SndLimBytesSender: 310699488
SubsequentTimeouts: 0
SumRTT: 59448
Timeouts: 0
TimestampsEnabled: 1
WinScaleRcvd: 0
WinScaleSent: 9
DupAcksOut: 0
StartTimeUsec: 114657
Duration: 10028744
c2sData: 8
c2sAck: 6
s2cData: 6
s2cAck: 9
half_duplex: 0
link: 100
congestion: 0
bad_cable: 0
mismatch: 0
spd: 420.63
bw: 1268826.32
loss: 0.000000000
avgrtt: 0.87
waitsec: 0.00
timesec: 10.00
order: 0.0434
rwintime: 0.0432
sendtime: 0.9421
cwndtime: 0.0147
rwin: 0.5000
swin: 256.0000
cwin: 0.7623
rttsec: 0.000871
Sndbuf: 33554432
aspd: 0.00000
CWND-Limited: 171.84
minCWNDpeak: -1
maxCWNDpeak: -1
CWNDpeaks: -1

The theoretical network limit is 1268826.32 Mbps
The NDT server has a 16384.0 KByte buffer which limits the throughput 
to 293915.04 Mbps
Your PC/Workstation has a 63.0 KByte buffer which limits the 
throughput to 574.05 Mbps
The network based flow control limits the throughput to 875.20 Mbps

Client Data reports link is 'OC-48', Client Acks report link is 'OC-12'
Server Data reports link is 'OC-12', Server Acks report link is '10 Gig'

--

Maurice Volaski, 

Computing Support, Rose F. Kennedy Center
Albert Einstein College of Medicine of Yeshiva University