Missing line in "Follow UDP Stream" in wireshark -

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i streaming raw udp packets (rf data) gnu radio octave (or other program). data consists of 390625 4 byte floats per second. 1562500 bytes per second. when gnu radio streams udp, there no header or sequence number in udp data, it's raw floats. because localhost localhost, able use large mtu.

attached screenshot of wireshark after right clicking , doing "follow udp stream". there "blank" part of hex dump @ 0x6f38c8. don't understand means? (i know udp not provide reliable delivery , packets can dropped , arrive out of order @ moment). great!

wireshark blank line in udp stream hex dump

the blank part used barrier differentiate between 2 udp packets, solely convenience.

  • if track down exact data in normal wireshark window you'll notice data before blank part belongs udp packet , data after blank part belongs subsequent udp packet.

  • the hex numbers on left specify offset of first byte of line beginning of stream in direction (i.e. in half blank line, byte 0x08 has 0x6f38c8 bytes sent before in direction). since half blank line has 8 bytes, offset of next line 0x6f38c8 + 0x8 = 0x6f38d0. indicator blank part isn't used filler data couldn't represented due obscure reason.

  • note impossible wireshark know whether data lost , represent in manner, since udp unreliable (that is, unless underlying protocol maintains counters itself, , parsed wireshark).


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