NDT-DEV email list created

Revision: 563
Author:   

Date:     Tue Aug 30 05:44:49 2011
Log:      Added description of the C2S Throughput Test.
http://code.google.com/p/ndt/source/detail?r=563

Modified:
 /wiki/NDTTestMethodology.wiki

=======================================
--- /wiki/NDTTestMethodology.wiki       Tue Aug 30 04:36:41 2011
+++ /wiki/NDTTestMethodology.wiki       Tue Aug 30 05:44:49 2011
@@ -79,12 +79,24 @@
 || "3" || There was no connection to the ephemeral port within the  
specified time ||

 === C2S Throughput Test ===
- * A block of pseudo random data is generated on the client and stored in  
memory.
- * The client repeatedly transmits this data to the server for 10 seconds.
- * The server acknowledges receipt of this data and then discards it.
- * The server calculates the average throughput by dividing the number of  
bytes sent by the test time.
- * The server also makes measurements on a per-packet basis, calculating  
the capacity of the e2e path.
- * Results from the test are returned to the client at the conclusion of  
the test.
+
+The C2S throughput test tests the achievable network bandwidth from the  
client to the server by performing a 10 seconds memory-to-memory data  
transfer.
+
+A detailed description of all of the C2S protocol messages can be found in  
the [NDTProtocol#C2S_throughput_test NDT Protocol document].
+
+As a first step the server binds an ephemeral port and notify the client  
about this port number.
+
+Next, the client connects to the server's ephemeral port. When the  
connection is successfully established, the server initializes the  
following routines:
+ * libpcap routines to perform packet trace used by the Bottleneck Link  
Detection algorithm.
+ * [NDTDataFormat#tcpdump_trace tcpdump trace] to dump all packets sent  
during the C2S throughput test on the newly created connection. This  
tcpdump trace dump is only started when the `-t, --tcpdump` options are set.
+ * [NDTDataFormat#web100_snaplog_trace web100 snaplog trace] to dump  
web100 kernel MIB variables' values written in a fixed time (default is 5  
msec) increments during the C2S throughput test for the newly created  
connection. This snaplog trace dump is only started when the `--snaplog`  
option is set.
+
+In the next step the client starts a 10 seconds throughput test using the  
newly created connection. The NDT client sends packets as fast as possible  
(i.e. without any delays) during the test. These packets are written using  
the 8192 Byte buffer containing a pre-generated pseudo random data  
(including only US-ASCII printable characters).
+
+When the 10 seconds throughput test is over, the server sends its  
calculated throughput value to the client. This throughput value is  
calculated using the following formula:
+{{{
+THROUGHPUT_VALUE = 8 * TRANSMITTED_BYTES / 1000 / TEST_DURATION_SECONDS
+}}}

 === S2C Throughput Test ===
  * A block of pseudo random data is generated on the server and stored in  
memory.