ndt-users list created

[Rich Carlson <>]

Lize;

These are part of the Web100 triage values.  The web100 kernel maintains 
3 possible states for a TCP connection.  These are sender limited (pkts 
can't leave the host because the sender's TCP window is closed - waiting 
for ACK's), receiver limited (the receiver's TCP window is closed - 
waiting for data to move up to the application), or network limited 
(either the Congestion window is limiting the flow, or no other limit is 
being hit).

As the NDT server streams data to the client the kernel records what 
state it was in when it stopped sending.  In this case 40% of the time 
the flow stops because the NDT server reached the max value for the TCP 
transmit window.  The other 60% of the time it was in the network 
limited state.  The More Details page will also include counters that 
tell you how many times the state changed.

This seems to indicate that you have not tuned the NDT server and it is 
becoming the bottleneck for the test.  I.E. the server can't send data 
faster because the TCP xmit window is too small.

What link speeds are you using?
What is the server's CPU utilization?
What are the TCP tuning parameters set to?

Rich

On 4/1/2010 5:53 AM, 

 wrote:
> This connection is sender limited 39.55% of the time.
> This connection is network limited 60.45% of the time.
>
> excuse me, i don't understand what does the two line above mean
> could anyone explain for me?