NDT-DEV email list created

Revision: 588
Author:   

Date:     Fri Sep  2 02:20:56 2011
Log:      Feedback based modifications in the Middlebox Test section.
http://code.google.com/p/ndt/source/detail?r=588

Modified:
 /wiki/NDTTestMethodology.wiki

=======================================
--- /wiki/NDTTestMethodology.wiki       Thu Sep  1 10:09:04 2011
+++ /wiki/NDTTestMethodology.wiki       Fri Sep  2 02:20:56 2011
@@ -28,11 +28,11 @@

 === Middlebox Test ===

-The middlebox test is a short throughput test from the server to the  
client with a limited CWND to check for a duplex mismatch condition.  
Moreover, this test uses a pre-defined MSS value to check if any  
intermediate node will modify its connection settings.
+The middlebox test is a short throughput test from the server to the  
client with a limited CWND ([http://en.wikipedia.org/wiki/Congestion_window  
congestion window] - one of the factors that determines the number of bytes  
that can be outstanding at any time) to check for a duplex mismatch  
condition. Moreover, this test uses a pre-defined MSS value to check if any  
intermediate node will modify its connection settings.

 A detailed description of all of the MID protocol messages can be found in  
the [NDTProtocol#Middlebox_test NDT Protocol document].

-As a first step the server binds an ephemeral port and notify the client  
about this port number. The server also sets MSS on this port to 1456  
(strange value).
+As a first step the server binds an ephemeral port and notify the client  
about this port number. The server also sets MSS on this port to 1456 (a  
strange value that it is unlikely a routers will have been tested with, so  
this also tests that they can handle such weird MSS sizes).

 Next, the client connects to the server's ephemeral port. When the  
connection is successfully established, the server sets the maximum value  
of the congestion window for this connection to `2 * (The current maximum  
segment size (MSS))`.

@@ -42,6 +42,8 @@
 {{{
 BUFFER_SIZE * 16 < ((Next Sequence Number To Be Sent) - (Oldest  
Unacknowledged Sequence Number) - 1)
 }}}
+
+The both `"Next Sequence Number To Be Sent"` and `"Oldest Unacknowledged  
Sequence Number"` values are obtained from the connection with the help of  
the [http://www.web100.org/ web100] library.

 When the 5 seconds throughput test is over, the server sends the following  
results to the client:

@@ -49,9 +51,9 @@
 || !WinScaleSent || The value of the transmitted window scale option if  
one was sent; otherwise, a value of -1. ||
 || !WinScaleRcvd || The value of the received window scale option if one  
was received; otherwise, a value of -1. ||

-Next, the client sends its calculated throughput value to the server. This  
throughput value is calculated using the following formula:
+Next, the client sends its calculated throughput value to the server. The  
throughput value is calculated by taking the transmitted bytes over the  
duration of the test. This value, in Bps, is then converted to kbps. This  
can be shown by the following formula:
 {{{
-THROUGHPUT_VALUE = 8 * TRANSMITTED_BYTES / 1000 / TEST_DURATION_SECONDS
+THROUGHPUT_VALUE = (TRANSMITTED_BYTES / TEST_DURATION_SECONDS) * 8 / 1000
 }}}

 === Simple Firewall Test ===