In my current set up I am running a real CAN-bus with three different devices to produce ISO-TP messages and one Ethernet adapter used as a sink for those messages.

1. A real ECU, that quickly responds to the Flow Control Frame. I can see the full conversation via candump and the assembled message via isotpsniffer and isotprecv (which is used to produce the Consecutive Frame).
2. A second adapter, USB, to generate messages on my own. Works just as 1. does. All raw CAN frames visible via candump and the assembled PDUs via isotpsniffer and isotprecv.
3. The curious one. A OBD-Simulator. Once again I can see all messages via candump and isotpsniffer can reassemble them, but isotprecv doesn't! Could this be caused as the OBD simulator responds quite slow? About 2ms for the first CF after the Flow Control Frame but 50ms till the second/last CF after the FCF. Maybe a timeout? It's weird as isotpsniffer seems like it doesn't timeout in this way.

$ isotprecv -s 7E0 -d 7E8 can0 -p 0 -l

$ candump -L can0,7FF:700 
(0000012752.119897) can0 7DF#0209020000000000
(0000012752.121322) can0 7E8#1014490201574458
(0000012752.121678) can0 7E0#3000000000000000
(0000012752.122951) can0 7E8#212D53494D303031
(0000012753.171596) can0 7E8#2239323132333435

$ isotpsniffer -s 7E0 -d 7E8 can0
 can0  7E8  [20]  49 02 01 57 44 58 2D 53 49 4D 30 30 31 39 32 31 32 33 34 35  - 'I..WDX-SIM0019212345'