NDT-DEV email list created

Revision: 601
Author:   

Date:     Mon Sep  5 03:37:19 2011
Log:      Added description of the duplex mismatch condition.
http://code.google.com/p/ndt/source/detail?r=601

Modified:
 /wiki/NDTTestMethodology.wiki

=======================================
--- /wiki/NDTTestMethodology.wiki       Mon Sep  5 03:23:38 2011
+++ /wiki/NDTTestMethodology.wiki       Mon Sep  5 03:37:19 2011
@@ -173,6 +173,8 @@

 === Duplex Mismatch Detection ===

+Duplex mismatch is a condition whereby the host Network Interface Card  
(NIC) and building switch port fail to agree on this basic network  
operating parameter. While this failure will have a large impact on  
application performance, basic network connectivity still exists. This  
means that normal testing procedures (e.g., ping, traceroute) will report  
that no problem exists while real applications will run extremely slowly.
+
 The NDT contains two heuristics for the duplex mismatch detection.

 A duplex mismatch is detected by the Old Duplex-Mismatch algorithm when  
the connection is congestion limited 90% of the time, the !WiFi is not  
detected, the [NDTTestMethodology#Speed_estimate speed estimate] is greater  
than 2Mibps, there is a lot of packets retransmissions and the S2C  
throughput speed is much smaller than expected.