[nos-bbs] Interested in REPEAT packet statistics?

George [ham] VerDuin k8rra at ameritech.net
Sun Apr 11 13:23:04 EDT 2010

Greeting all.
This is an FYI sorta note -- trivia about jnos & AMPRnet.

On my jnos node I see some un-necessary packet duplication.
There are a few reasons -- some I can help, others require re-programming.
The subject of this note is only "how many" duplicates show up at my 

What follows is a summary of TCP packets received from others at my node.
It is broken into "datagram" and "vc" because I support both modes.
What I see is that VC causes a lot more duplication of TCP traffic,
   -- and that does include AX.25 Level II duplication.

 >>>> The trace file is named: v1
The period ends:
   Sun Apr 11 10:44:35 2010 - vhf recv:
The period begins:
   Mon Mar 22 12:27:09 2010 - vhf recv:
That means the data period is a couple hours short of 20 days.

The total UI packets = 2083
The DUPLICATE UI packet counts by repeat number.
      81       2 TCP: 1029->25 Seq xe927e1da Ack xec3e408c ACK PSH FIN 
Wnd 2048
       8       3 TCP: 1051->25 Seq xbe0b00b Ack xdd7d030 ACK PSH Wnd 2048
TOTAL: 97 of 2083 ==> 4.5% of traffic is duplicate

The total I packets = 511
The DUPLICATE I packet counts by repeat number.
      38       2 TCP: 1036->25 Seq xc3aa000 SYN Wnd 2048 MSS 512
      14       3 TCP: 23->1034 Seq x971d8000 Ack xc7211001 ACK PSH SYN 
Wnd 5840
      12       4 TCP: 1046->25 Seq x57050000 SYN Wnd 2048 MSS 512
       5       5 TCP: 1041->25 Seq x31a05000 SYN Wnd 2048 MSS 512
       3       6 TCP: 25->1027 Seq x781b9092 Ack xc16484a0 ACK Wnd 5840
       2       8 TCP: 25->1027 Seq x781b9092 Ack xc1647a80 ACK Wnd 5840
TOTAL: 151 of 511 ==> 29.5% of traffic is duplicate

How to read the above?
The line just above "TOTAL: 151..." says:
    "on 2 seperate occurrences in the past 20 days, one packet was 
repeated 8 times."
    "A sample TCP header record is included"

How to repeat the above?
A Linux script is attached for your amusement.
If you have jnos trace turned ON for a RF interface, you can compute 
your own statistics.

Now What?

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: adup
URL: <http://lists.tapr.org/pipermail/nos-bbs_lists.tapr.org/attachments/20100411/7459ba68/attachment.ksh>

More information about the nos-bbs mailing list