#3 pending
Kenny Richards

Header checksum mismatch: expected 0x0369

Reported by Kenny Richards | August 23rd, 2015 @ 10:45 AM

Getting header checksum mismatch errors this morning (8/23) when trying to connect to REF001 A/C.

-[BTRLinkDriver processFrame:] [Line 439] Header checksum mismatch: expected 0x5A2D calculated 0x712B (error for REF001-C) -[BTRLinkDriver processFrame:] [Line 439] Header checksum mismatch: expected 0x0369 calculated 0xFB22 (error for REF001-A/B)

Able to connect to other reflectors fine, like REF035-C and REF029-C.

Should this type of thing be bubbled up to the user? I am now running console all the time, filtering for Buster messages. (Because I am that weird)

Comments and changes to this ticket

  • mcdermj (at xenotropic)

    mcdermj (at xenotropic) August 23rd, 2015 @ 01:24 PM

    • State changed from “new” to “open”

    This isn't really a connection issue per se. Each D-STAR header frame has a checksum over it. It's part of the D-STAR over-the-air specification. It's not involved in frames with AMBE data, only frames with header data. I'm assuming this is because the AMBE data already has FEC applied, so a checksum is really overkill. These are technically bad packets according to the spec. I did see some notes in Johnathan's code, though, that implied that D-Plus checksums are "unreliable" (See https://github.com/dl5di/OpenDV/blob/master/ircDDBGateway/Common/DP...).

    This isn't really something that the user can do anything about. Either the header is per spec, or it's not, so it's not really appropriate to percolate up to the user.

    Currently Buster discards header packets with a bad checksum. What should probably be done is that for D-Plus, we should warn about those packets only and not discard them. This is what ircDDBGateway does.

  • mcdermj (at xenotropic)

    mcdermj (at xenotropic) August 24th, 2015 @ 02:13 PM

    • State changed from “open” to “pending”

    Implemented optional checksum checking.

    Git 360df18.

  • mcdermj (at xenotropic)

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A D-STAR reflector client.

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