ndt-users list created

[Maurice Volaski <>]

I am using this program again, and I seem to always be getting some 
sort of "unknown link type" error, such as "unable to determine the 
bottleneck link type". OTOH, it does seem to be determining the 
duplex state properly.

I'm now running our Gentoo NDT box with web100-patched kernel 2.6.26 
running on VMware 2 on my Mac running 10.5.5, all under gigabit. The 
user tools are 1.7 and NDT reports 5.5.4a in the applet.

Here's some sample output
WEB100 Enabled Statistics:
Checking for Middleboxes . . . . . . . . . . . . . . . . . .  Done
checking for firewalls . . . . . . . . . . . . . . . . . . .  Done
running 10s outbound test (client-to-server [C2S]) . . . . . 655.54Mb/s
running 10s inbound test (server-to-client [S2C]) . . . . . . 484.16Mb/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  ------
Interprocess communications failed, unknown link type.
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 = 0.95 msec; the Packet size = 
1448 Bytes; and
No packet loss - but packets arrived out-of-order 5.51% of the time
S2C throughput test: Packet queuing detected: 1.59%
This connection is receiver limited 6.11% of the time.
This connection is sender limited 92.80% of the time.
This connection is network limited 1.09% 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: 87561
AckPktsOut: 0
BytesRetrans: 0
CongAvoid: 0
CongestionOverCount: 0
CongestionSignals: 0
CountRTT: 79576
CurCwnd: 98464
CurRTO: 204
CurRwinRcvd: 65080
CurRwinSent: 6144
CurSsthresh: 2147483647
DSACKDups: 0
DataBytesIn: 0
DataBytesOut: 606684560
DataPktsIn: 0
DataPktsOut: 418134
DupAcksIn: 4828
ECNEnabled: 0
FastRetran: 0
MaxCwnd: 98464
MaxMSS: 1448
MaxRTO: 216
MaxRTT: 72
MaxRwinRcvd: 65535
MaxRwinSent: 6144
MaxSsthresh: 0
MinMSS: 1448
MinRTO: 204
MinRTT: 0
MinRwinRcvd: 8648
MinRwinSent: 5792
NagleEnabled: 1
OtherReductions: 0
PktsIn: 87561
PktsOut: 418134
PktsRetrans: 0
RcvWinScale: 9
SACKEnabled: 3
SACKsRcvd: 0
SendStall: 0
SlowStart: 66
SampleRTT: 0
SmoothedRTT: 4
SndWinScale: 0
SndLimTimeRwin: 612037
SndLimTimeCwnd: 109523
SndLimTimeSender: 9297644
SndLimTransRwin: 19242
SndLimTransCwnd: 9
SndLimTransSender: 19252
SndLimBytesRwin: 471048792
SndLimBytesCwnd: 271608
SndLimBytesSender: 135364160
SubsequentTimeouts: 0
SumRTT: 75384
Timeouts: 0
TimestampsEnabled: 1
WinScaleRcvd: 0
WinScaleSent: 9
DupAcksOut: 0
StartTimeUsec: 553581
Duration: 10019463
c2sData: -1
c2sAck: -1
s2cData: -1
s2cAck: -1
half_duplex: 0
link: 100
congestion: 0
bad_cable: 0
mismatch: 0
spd: 484.42
bw: 11661.69
loss: 0.000001000
avgrtt: 0.95
waitsec: 0.00
timesec: 10.00
order: 0.0551
rwintime: 0.0611
sendtime: 0.9280
cwndtime: 0.0109
rwin: 0.5000
swin: 256.0000
cwin: 0.7512
rttsec: 0.000947
Sndbuf: 33554432
aspd: 0.00000
CWND-Limited: 170.82
minCWNDpeak: -1
maxCWNDpeak: -1
CWNDpeaks: -1

The theoretical network limit is 11661.69 Mbps
The NDT server has a 16384.0 KByte buffer which limits the throughput 
to 270327.34 Mbps
Your PC/Workstation has a 63.0 KByte buffer which limits the 
throughput to 527.98 Mbps
The network based flow control limits the throughput to 793.24 Mbps

Client Data reports link is 'System Fault', Client Acks report link 
is 'System Fault'
Server Data reports link is 'System Fault', Server Acks report link 
is 'System Fault'
--

Maurice Volaski, 

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