ndt-users list created

[Richard Carlson <>]

Hi Alex;

I'm the developer of the NDT software so I'll try and answer your question.

I just brought up a Fedora Core 2 server with the 2.6.10 w/2.5.2 web100 
patch.  The NDT code operated properly on this server.

The 'System Fault" message indicates that the web100srv process is unable 
to capture raw data from the network interface.  The possible problems are:

1) The server is monitoring the wrong network interface.  If your server 
has multiple ethernet interfaces, the libpcap routine will pick the 'first' 
interface in the list (eth0).  In this case you can specify the correct 
interface using the -i option (e.g. web100srv -i eth1).

2) The web100srv process needs root access to obtain raw access to the 
network interface.  Make sure you have the correct ownership and permissions.

There should be some log entries in the /var/log/messages or 'dmesg' log 
file that can tell you what interface is being used of if the interface 
failed to enter promiscuous mode.

Check the interface id first and then look at the ownership/permissions and 
let us know if you still have problems.

Regards;
Rich Carlson

At 04:02 PM 1/22/2005 +0300, Alex Y Fadeyev wrote:
> Hello.
>
> NDT I've installed unable to determine bottleneck link type.
> Configuration:
> NDT-3.0.23
> web100 userland Alpha 1.4 (I've tried 1/3 - same results)
> web100 kernel-patch 2.5.2 on kernel 2.6.10 from kernel.org.
> libpcap-0.8.3
> Server system - Fedora Core 3 on AMD x86_64 uniprocessor machine. 1Gbit/s 
> connection.
> Client - Windows XP. 100 Mbit/s LAN connection.
> As I notice this because
> Client Data reports link is 'System Fault', Client Acks report link is 
> 'System Fault' (see in More datails below)
> web100srv has been runned with -x options and without - there are same 
> results in both cases.
>
> I shall be grateful for any advice.
>
> Example of ouput:
> Main:
> TCP/Web100 Network Diagnostic Tool v5.3.3a
> click START to begin
> Checking for Middleboxes . . . . . . . . . . . . . . . . . .  Done
> running 10s outbound test (client to server) . . . . . 94.07Mb/s
> running 10s inbound test (server to client) . . . . . . 94.60Mb/s
> Server unable to determine bottleneck link type.
>
> click START to re-test
>
> Statistics:
> WEB100 Enabled Statistics:
> Checking for Middleboxes . . . . . . . . . . . . . . . . . .  Done
> running 10s outbound test (client to server) . . . . . 94.07Mb/s
> running 10s inbound test (server to client) . . . . . . 94.60Mb/s
>
>    ------  Client System Details  ------
> OS data: Name = Windows XP, Architecture = x86, Version = 5.1
> Java data: Vendor = Sun Microsystems Inc., Version = 1.5.0
>
>    ------  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 = 5.46 msec; the Packet size = 1460 
> Bytes; and
> No packet loss - but packets arrived out-of-order 0.03% of the time
> This connection is receiver limited 83.56% of the time.
> This connection is sender limited 16.33% 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: OFF
> RFC 1323 Window Scaling: ON
> Packet size is preserved End-to-End
> Server IP addresses are preserved End-to-End
> Client IP addresses are preserved End-to-End
>
> More datails:
> WEB100 Kernel Variables:
> Client: localhost/127.0.0.1
> AckPktsIn: 40908
> AckPktsOut: 0
> BytesRetrans: 0
> CongAvoid: 0
> CongestionOverCount: 0
> CongestionSignals: 0
> CountRTT: 40895
> CurCwnd: 67160
> CurMSS: 1460
> CurRTO: 205
> CurRwinRcvd: 65535
> CurRwinSent: 5840
> CurSsthresh: -616
> DSACKDups: 0
> DataBytesIn: 0
> DataBytesOut: 120942818
> DataPktsIn: 0
> DataPktsOut: 80483
> DupAcksIn: 14
> ECNEnabled: 0
> FastRetran: 0
> MaxCwnd: 67160
> MaxMSS: 1460
> MaxRTO: 206
> MaxRTT: 6
> MaxRwinRcvd: 65535
> MaxRwinSent: 5840
> MaxSsthresh: 0
> MinMSS: 1460
> MinRTO: 201
> MinRTT: 0
> MinRwinRcvd: 567
> MinRwinSent: 5840
> NagleEnabled: 1
> OtherReductions: 0
> PktsIn: 40914
> PktsOut: 80483
> PktsRetrans: 0
> X_Rcvbuf: 87380
> RcvWinScale: -1
> SACKEnabled: 3
> SACKsRcvd: 0
> SendStall: 0
> SlowStart: 44
> SampleRTT: 5
> SmoothedRTT: 5
> X_Sndbuf: 131072
> SndWinScale: -1
> SndLimTimeRwin: 8364151
> SndLimTimeCwnd: 10895
> SndLimTimeSender: 1634675
> SndLimTransRwin: 3331
> SndLimTransCwnd: 10
> SndLimTransSender: 3340
> SndLimBytesRwin: 108172272
> SndLimBytesCwnd: 202876
> SndLimBytesSender: 12567670
> SubsequentTimeouts: 0
> SumRTT: 223227
> Timeouts: 0
> TimestampsEnabled: 0
> WinScaleRcvd: -1
> WinScaleSent: -1
> DupAcksOut: 0
> StartTimeUsec: 725862
> Duration: 10014196
> c2sData: -1
> c2sAck: -1
> s2cData: 8
> s2cAck: -1
> half_duplex: 0
> link: 100
> congestion: 0
> bad_cable: 0
> mismatch: 0
> spd: 0.00
> bw: 2040.64
> loss: 0.000001000
> avgrtt: 5.46
> waitsec: 0.00
> timesec: 10.00
> order: 0.0003
> rwintime: 0.8356
> sendtime: 0.1633
> cwndtime: 0.0011
> rwin: 0.5000
> swin: 1.0000
> cwin: 0.5124
> rttsec: 0.005459
> Sndbuf: 131072
>
> Checking for mismatch condition
>    (cwndtime > .3) [0.00>.3], (MaxSsthresh > 0) [0>0],
>     (PktsRetrans/sec > 2) [0>2], (estimate > 2) [2040.64>2]
> Checking for mismatch on uplink
>    (speed > 50 [0>50], (xmitspeed < 5) [94.07<5]
>    (rwintime > .9) [0.83>.9], (loss < .01) [1.0E<.01]
> Checking for excessive errors condition
>    (loss/sec > .15) [1.0E>.15], (cwndtime > .6) [0.00>.6],
>    (loss < .01) [1.0E<.01], (MaxSsthresh > 0) [0>0]
> Checking for 10 Mbps link
>    (speed < 9.5) [0<9.5], (speed > 3.0) [0>3.0]
>    (xmitspeed < 9.5) [94.07<9.5] (loss < .01) [1.0E<.01], (mylink > 0) 
> [0.0>0]
> Checking for Wireless link
>    (sendtime = 0) [0.16=0], (speed < 5) [0<5]
>    (Estimate > 50 [2040.64>50], (Rwintime > 90) [0.83>.90]
>     (RwinTrans/CwndTrans = 1) [3331/10=1], (mylink > 0) [0.0>0]
> Checking for DSL/Cable Modem link
>    (speed < 2) [0<2], (SndLimTransSender = 0) [3340=0]
>     (SendTime = 0) [0.1633=0], (mylink > 0) [0.0>0]
> Checking for half-duplex condition
>    (rwintime > .95) [0.83>.95], (RwinTrans/sec > 30) [333.1>30],
>     (SenderTrans/sec > 30) [334.0>30], OR (mylink <= 10) [0.0<=10]
> Checking for congestion
>    (cwndtime > .02) [0.00>.02], (mismatch = 0) [0=0]
>    (MaxSsthresh > 0) [0>0]
>
> estimate = 2040.64 based on packet size = 11Kbits, RTT = 5.46msec, and 
> loss = 1.0E-6
> The theoretical network limit is 2040.64 Mbps
> The NDT server has a 128.0 KByte buffer which limits the throughput to 
> 183.18 Mbps
> Your PC/Workstation has a 63.0 KByte buffer which limits the throughput to 
> 91.59 Mbps
> The network based flow control limits the throughput to 93.86 Mbps
>
> Client Data reports link is 'System Fault', Client Acks report link is 
> 'System Fault'
> Server Data reports link is 'OC-48', Server Acks report link is 'System Fault'
>
>
>
> --
> Sinrecery Yours,
> Alex Y. Fadeyev
> MIPT-telecom http://telecom.mipt.ru
> Tel.:   +7 095 576-4381
> Fax.:   +7 095 576-4563
> e-mail: