NDT-DEV email list created

Revision: 603
Author:   

Date:     Mon Sep  5 04:07:29 2011
Log:      Added a new known issues/limitations summary section.
http://code.google.com/p/ndt/source/detail?r=603

Modified:
 /wiki/NDTTestMethodology.wiki

=======================================
--- /wiki/NDTTestMethodology.wiki       Mon Sep  5 03:47:37 2011
+++ /wiki/NDTTestMethodology.wiki       Mon Sep  5 04:07:29 2011
@@ -56,7 +56,7 @@
 THROUGHPUT_VALUE = (TRANSMITTED_BYTES / TEST_DURATION_SECONDS) * 8 / 1000
 }}}

-==== Known issues ====
+==== Known issues (Middlebox Test) ====

 The formula used to find out when to temporarily stop sending packets is  
probably wrong. The idea was to use this as a part of the duplex mismatch  
detection, with a max of 2 packets in flight the Ethernet half-duplex  
sender should never see a collision so the throughput would be higher even  
though the buffer is limited.

@@ -167,7 +167,7 @@

 The detected link type is indicated by the bin with the most packet pairs  
in it.

-==== Known limitations ====
+==== Known limitations (Bottleneck Link Detection) ====

 The results are quantized, meaning that the NDT doesn’t recognize  
fractional link speed (Ethernet, T3, or FastE). It also wouldn’t detect  
bonded Etherchannel interfaces.

@@ -199,7 +199,7 @@
  * The [NDTTestMethodology#'Receiver_Limited'_state_time_share 'Receiver  
Limited' state time share] *is greater than 90%*
  * The [NDTTestMethodology#Packet_loss packet loss] *is less than 1%*

-==== Known limitations ====
+==== Known issues/limitations (Duplex Mismatch Detection) ====

 The Old Duplex-Mismatch algorithm does not work with multiple simultaneous  
tests. In order to enable this algorithm, the multi-test mode must be  
disabled (so the `-m, --multiple` options cannot be set).

@@ -245,7 +245,7 @@
  * The [NDTTestMethodology#Packet_loss packet loss] *is less than 1%*
  * The [NDTTestMethodology#Packets_arriving_out_of_order out of order  
packets proportion] *is less than 3.5%*

-==== Known issues ====
+==== Known issues (Link Type Detection Heuristics) ====

 The [NDTTestMethodology#DSL/Cable_modem DSL/Cable modem] heuristic appears  
to be broken now because the DSL/Cable modems commonly go above 2Mbps  
nowadays.

@@ -257,7 +257,7 @@
  * The [NDTTestMethodology#Packet_loss packet loss] *is less than 1%*
  * The maximum slow start threshold, excluding the initial value, *is  
greater than 0*

-==== Known limitations ====
+==== Known issues (Faulty Hardware Link Detection) ====

 The condition "The  
[NDTTestMethodology#'Congestion_Limited'_state_time_share 'Congestion  
Limited' state time share] divided by the  
[NDTTestMethodology#Total_test_time_in_seconds total test time in seconds]  
is greater than 0.6" cannot be met, because the state time share is less  
than 1 and the total test time in seconds is around 10, so this result will  
be always less than 0.1.

@@ -421,7 +421,7 @@

 where p is the loss probability.

-==== Known limitations ====
+==== Known issues (Speed estimate) ====

 The speed estimate should be computed to receive Mbps instead of Mibps.  
This is the only variable in the NDT that is kept in Mibps, so it might  
lead to the inconsistent results when comparing it with the other values.

@@ -461,3 +461,13 @@
 where:
  * *!TotalTestTime* - [NDTTestMethodology#Total_test_time Total test time]
  * *!SndLimTimeSender* - The cumulative time spent in the 'Sender Limited'  
state
+
+== Known issues/limitations ==
+
+Some issues/limitations have been found in the NDT regarding the following  
areas:
+ * [NDTTestMethodology#Known_issues_(Middlebox_Test) Middlebox Test]
+ * [NDTTestMethodology#Known_limitations_(Bottleneck_Link_Detection)  
Bottleneck Link Detection]
+ *  
[NDTTestMethodology#Known_issues/limitations_(Duplex_Mismatch_Detection)  
Duples Mismatch Detection]
+ * [NDTTestMethodology#Known_issues_(Link_Type_Detection_Heuristics) Link  
Type Detection Heuristics]
+ * [NDTTestMethodology#Known_issues_(Faulty_Hardware_Link_Detection)  
Faulty Hardware Link Detection]
+ * [NDTTestMethodology#Known_issues_(Speed_estimate) Speed estimate]