Hello. We have a custom pktgen tool which supports old version of the ntcap (9.0.2). It reads the pcap files, orchastrates them so that they are sent at correct rate, time etc., and sends them. I’m updating the code base to NTAPI 11.0.7, so that NT100E3 adapter can be used for traffic gen. I’m writing code based on the ‘net/transmit_segment/transmit_segment_example.c’ from the driver documentation package.  I follow the algorithm from that example (a lot of copy-paste with some adaptations), that is:

1. create TX stream
2. get host buffer for that TX stream
3. create packet netbuf
4. fill packet netbuf (the segment) with packets, add TX ignore packets if space left in segment
5. release host buffer
6. go to step 2

The NTAPI calls return NT_SUCCESS. But when generating at a rate higher then ~6700 Mbps I encounter the issue very few packets are actually transimtted. And the ntlog tool displays the error like in the title of this question. All NTAPI calls reside in the same background thread (but different then main thread). The only information I found about the error is:

”
42177
(Support)
When dynamically assigning, deleting and reassigning Inline Tx NTPL streams
– in certain scenarios the result is that the inline stream data would be received
but never properly inline transmtted with NTPL dynamically reassigned.
Typicallly the ntsservice log will contain messages like. Adapter 0:
Hbh4gaTxMonThreadFunc: Tx TBH delineation error on Tx feed 4: some
packets may not have been transmitted
”

But that does not help me at all. I checked the original pktgen tool from the driver suite and it seem to work without such issues. When I tried sending on timestamp (also from examples) the result is the same, bottleneck at roughly 6700 Mbps.

Could anybody point me to the right direction?  (What additional information do you need to help me with this issue?)

Kind regards