What happens when option 4 'HeaderTrailerLink' (see link) for data forwarding is defined in a smart-serial protocol?
https://docs.dataminer.services/develop/devguide/Connector/ConnectionsSmartSerialDataForwarding.html
Use case: the connector should receive a response from the device, but it doesn't seem to be forwarded. Therefore, I enabled the logging in SLPort.txt (1) to see the incoming data for that connection and also used Wireshark (2) for more information.
The Wireshark capture shows the request is sent to the device and the response is indeed received by DataMiner, divided in 4 packets. The logging in SLPort.txt also shows the response is received, but the data is divided into 2.
Why is the first response packet shown seperatly in the logging and why are the other 3 packets combined? Could this be the reason the response isn't forwarded?
(1)
2023/02/09 15:08:28.961|SLPort.exe 10.2.2235.1626|19532|14676|CSmartIP::ProcessIncomming
|DBG|4|Incoming data from 10.128.13.150:5554 (total length: 1460 bytes)
2023/02/09 15:08:28.963|SLPort.exe 10.2.2235.1626|19532|14676|CSmartIP::ProcessIncomming
|DBG|4|Incoming data from 10.128.13.150:5554 (total length: 3894 bytes)
(2)
SLPort scans the incoming data stream for the defined headers and trailers. Once a header is detected, SLPort will only search for the corresponding linked trailer. It will disregard any other headers or trailers within the data stream, even the same header will be skipped. Once the trailer is found, SLPort will forward the data between the header and trailer, including both the header and trailer themselves, to SLProtocol. Any data outside of the header-trailer matches will be discarded.
Hi Stijn,
- Are you using header and trailer or only trailer with the HeaderTrailerLink option?
- In case of the latter, is it possible that the first package already contains the trailer?
Hi Jens,
I am using both a header and a trailer.
Checked the response and the trailer does not appear in the first part of the data.
I also discovered that another response from the same request (almost similar data) does get forwarded. It seems arbitrary to me, but I probably lack some information.