[En-Nut-Discussion] NutOS reusing TCP acknowlegment number over PPP in low volume traffic

[Brett Abbott]

Hi

Im seeing NutOS continually resusing a single acknowledgment number in 
TCP packets when under low load/volume.  Has anyone else seen this?  Is 
it as expected?

Im using the Ethenut2, latest NutOS (Pathched through to November 04)

We are using TCP over PPP.  a single TCP packet is sent from the 
ethernut every 5 minutes and a single TCP ACK packet is received back 
from the host.  When the traffic continues like this, nutOS will send 
exactly the same acknowledgement number every packet.  which works ok 
until the load increases at which point there is a bit of confusion but 
typically gets worked out (but with more packets than ideal).  After the 
higher load, and the pattern of traffic returns to once every 5 minutes, 
a new but different acknowledgement number is used from then on...  The 
host is using different ack numbers but the Ethernut is not.

Any ideas?  Im going to bring the patch level up to current over the 
next few days but dont see anything in the change log to suggest a cause.

Many Thanks
Brett

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Brett Abbott, Managing Director, Digital Telemetry Limited
Email: Brett.Abbott at digital-telemetry.com
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