Non-deterministic message delay

[PatrickS]

Dear PEAK support,

we're using the PCAN-Ethernet Gateway FD DR in socket mode (UDP). When having a deeper look into the sending/receiving times, we observed that we sometimes have some non-deterministic delays:

- On sender side (sending UDP packets to the gateway), we're sending the same message every 500ms. We checked those times and we are pretty sure that this timing is ensured quite precisely.
- On receiver side (receiving CAN packets from the gateway), we're expecting this message also every 500ms. When measuring the time difference between the reception of two CAN messages, this requirement is mostly fulfilled. However, there are also occurences, where we measure time differences of up to 507ms.

Our current interpretation is, that the gateway sometimes takes multiple milliseconds longer to forward this message than in most of the other cases.

I already saw in your user manual, that you're not able to give a fixed value for the signal delay. However, I would like to ask you whether this behavior would be expected to you. Personally I would expect the delay to be rather constant, as long as the network itself is not changed.

Thank you.
Patrick

[S.Grosjean]

Hi,

Thank you for your interest in the PEAK-System PCAN-Gateway products line.

As you wrote, we cannot guarantee any delay or real time period when routing IP packets, mainly because of the IP network itself and also because of the embedded system and its IP layer. Also, this sporadic additional delay of 7 ms is not something that surprises us too much because the priority of this gateway is mainly to connect CAN networks to each other, not to replace a CAN network.

Regards,