I am using version 3.4.0 of wireshark, 64-bits, running on a windows10 computer. I also have a TAP which provides me with all the packet data, from the beginning of the preamble to the end of the FCS. I have pcaps that include frames to which preemption has been applied (Clause 99 of IEEE 802.3-2018 and 6.7.1, 6.7.2 and 8.6.8 of IEEE 802.1Q-2018). The current dissector seems to have problems correctly reporting the express, frames to which preemption has been applied, particularly the fragments.... For example, the dissector recognizes the first fragment and provides information on this fragment, such as a good mCRC and that the frame has an SMD-S3. The second fragment, seems to be partially recognized, but it reports a Bad CRC, when there is a good mCRC. It lists the frame as a 2nd fragment, and even has all the data for the two fragments. For the third and last fragment, there is reported a Bad mCRC when there is in fact a good CRC. This fragment also seems to have lost the fact that it belongs to the other preceeding fragments. What can be done to fix this? Can I help? -Paul Andrews
