[Sls-slp] USLP emergency hardware command proposal

Kazz, Greg J (312B) greg.j.kazz at jpl.nasa.gov
Mon Nov 9 15:30:21 UTC 2015

Dear SLP WG,

Appologies that this information below was not included in the draft USLP white book as reported at the meeting. However, it was intended to be there and will be added. See proposal below. This emergency command format could be assigned to MAP ID 0 and/or VCID 0 (up for discussion).


Currently hardware commands are 64 bits in length, use BCH encoding in triple error detection mode.  If we were to offer a service that is uncoded using a 16 bit CRC, a fixed length of 64 bits they could accommodate a 16 bit command space..  Note: I am not proposing this alternative because I think that emergency commands should be LDPC encoded.  But if we adopt the same fixed length rule for VC0 then even for a 64 bit code block, by dropping the length and CRC, you get a 32 bit command space.  In fact, all VC 0 needs is the first 32 bits of the USLP transfer frame header below leaving 32 bits for command space.

We also feel that the TFDZ does not need a header thus the total TFDZ would contain the hardware command.

Here is what we got in the standard frame.

[cid:image003.png at 01D0DEB8.F2F33C00]

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