[Vm-dev] Re: SecureSession frame types
Robert Withers
robert.w.withers at gmail.com
Sun Dec 20 14:20:28 UTC 2015
My apologies for #2 below; what I said is wrong. The smallest message
will be 8 bytes, as the messageSpecification is not FEC encoded. I will
repair the doc as there are some issues with the spec and layout...done.
Once again the link is:
https://www.dropbox.com/s/zj2i1votg432b2p/FrameTypes.pptx?dl=0
* MessageSpecification is 8 bytes binary encoded.
* Header is always asn.1 encoded
* All messages may be FEC encoded with the FEC header asn.1 encoded.
* Data Message payload is encrypted.
Change query:
Regarding the Message Specification, with a hdrSize...I don't think we
need it. The message size includes everything + the 8 bytes spec. The
hdrType will specify the kind of message and header. The specific header
knows it's own size and layout. Therefor, we have 16bits free if we
keep an 8 byte msgSpec. Let's rework it to a 7 byte msgSpec as below.
Perhaps it is useful to be 64bit aligned, so leave it at 8. Thoughts?
Does this work?
*msgSpec: 7 bytes binary encoded*
* HeaderSpecification: 3 bytes
o multicastSymbol: 6 bits
o sanguinity: 7 bits
o msgVersion: 5 bits
o hdrType: 6 bits
* msgSize: 2nd word, 4 bytes
o 4 bytes (total size with msgSpec, header, payload sizes)
regards,
robert
On 12/20/2015 07:01 AM, Robert Withers wrote:
> Good morning, just a few comments and questions..
>
> 1) current 4bits for msgVersion and 4bits for hdrType. With 14
> messages and some not implemented (suspend/resume/...) we have
> little headroom in 4bits of hdrType. Shall I make the msgVersion
> 3bits and the hdrType 5bits?
>
> 2) the smallest interleaved FEC encoded msg is 30 bytes. With 8
> bytes of data: a msgSpec, using RS(15,9) with 4bit symbols, and 4
> symbol block interleaving, the smallest on the wire is 30 bytes.
> Without FEC enabled is it 8 bytes.
>
> 3) when run to the end of hdrType room, we can add a jump tag and
> have a second hdrType field as the 9th byte.
>
>
> Again, the valid document link is:
> https://www.dropbox.com/s/zj2i1votg432b2p/FrameTypes.pptx?dl=0
>
> Thank you,
> robert
>
>
>
> On 12/20/2015 06:20 AM, Clément Bera wrote:
>>
>>
>>
>> Hello,
>>
>> I tried to get your document but I got:
>>
>> Dropbox - error
>>
>> Is it only me ?
>>
>> 2015-12-20 11:31 GMT+01:00 Robert Withers <robert.w.withers at gmail.com
>> <mailto:robert.w.withers at gmail.com>>:
>>
>>
>> Excuse me for failing to complete this email./ I wanted to ask
>> for feedback on these structures, especially the header
>> specification word structure. So these fields make sense?
>>
>> thank you,
>> robert
>>
>>
>> On 12/20/2015 05:27 AM, Robert Withers wrote:
>>
>> I wrote up the various SecureSession frame types in
>> presentation document, which you can get here:
>> https://www.dropbox.com/s/3xfa5oqs8ihj88v/FrameTypes.pptx?dl=0
>>
>> These are not yet implemented, but it is progressing. Ne quid
>> nemis.
>>
>> thanks,
>>
>>
>> --
>> . .. .. ^,^ robert
>>
>>
>
> --
> . .. .. ^,^ robert
--
. .. .. ^,^ robert
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