Re: [libpcap] New DLT value Request - Wattstopper DLM (#401)

[Guy Harris <guy () alum mit edu>]

On Jan 9, 2015, at 4:11 PM, Steve Karg <skarg () users sourceforge net> wrote:

> > I.e., following the Family/Address/IR field, other families might not have the Sequence ID, Source and Destination 
> > MAC addresses, Opcode, and Payload Length followed by Payload?
>
> Yes, that is correct.

OK, so we should, for now, indicate that values other than 5 in the Family subfield mean that the subsequent data in 
the frame are unspecified.  If you can find documentation for the frame formats for the other families, we can update 
the spec.

> > Is the checksum family-code independent or might packets with other family codes not have it (or calculate the 
> > checksum differently)?
>
> I presume the checksum is family-code dependent (although by luck it
> might not be).

So that goes along with the above - we'll indicate that we only specify what it means for a Family code of 5.

> > What I meant was that you said "The 8 Legrand NITOO families are ..." - is this a protocol used only by Legrand, so 
> > that those are the only family codes used, or are there other vendors who might have their own set of families and 
> > family codes, different from the Legrand ones?
>
> This protocol is only used by Legrand and their subsidiary companies
> (i.e. WattStopper), as far as I know.

So we should assume that the Family subfield is always 3 bits and that the values always mean:

        0 - Cad Filaire
        1 - TopDog
        2 - CAD RF
        3 - CAD PLC
        4 - CAD IR
        5 - DLM
        6 or 7 - escape
        7 or 6 - DLM Bootloader

The information you quoted said "111=escape, and 111=DLM Bootloader"; I assume one of those 111's is supposed to be 
110.  Which one of them should be 110?
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