Hi, It seems Wireshark fails to decode captured packets with shortened preamble?
Normally Ethernet packets have a preamble and SFD like this: 55555555555555D5 But during transmission over Ethernet, sometimes the preamble arrives slightly shorter at the receiving end. Some bytes, or even half a byte(!), at the start of the preamble can go missing for various technical reasons. This is considered normal, and all Ethernet MACs are required to properly decode packets with shortened preamble, as well as packets where the preamble is a non-integer number of bytes. But it seems Wireshark does not? Decoding failure when preamble is shortened: [cid:[email protected]] Normal preamble, decoding successful: [cid:[email protected]] I have attached a pcapng file with these two packets. Timmy Brolin M.SC. Computer Systems Engineering HMS Industrial Networks AB Stationsgatan 37, Box 4126 300 04 Halmstad, Sweden Email: [email protected]<mailto:[email protected]> Direct: +46 35 17 29 32 [cid:[email protected]] HALMSTAD | BARCELONA | BEIJING | BOSTON | BUCHEN | CHICAGO | COVENTRY | DUBAI | HEDEL | IGUALADA | KARLSRUHE | MILAN | MULHOUSE | NIVELLES | PUNE | RAVENSBURG | SEOUL | SINGAPORE | TOKYO | WETZLAR www.hms-networks.com
shortened_preamble.pcapng
Description: shortened_preamble.pcapng
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