[Sls-slp] CCSDS definition of Protocol IDs

Gian.Paolo.Calzolari at esa.int Gian.Paolo.Calzolari at esa.int
Fri Feb 5 14:48:56 UTC 2016

Sorry Keith but I am quite puzzled as the mail you forward is not the mail 
I sent......
I just said:  Also to be said that USLP is a little schizophrenic as 
sometimes it looks to saving bits and sometimes emphasises that USLP 
framers are so long that it is not worth saving bits    :o) 


Gian Paolo

From:   "Scott, Keith L." <kscott at mitre.org>
To:     "Gian.Paolo.Calzolari at esa.int" <Gian.Paolo.Calzolari at esa.int>, 
"Tomaso.deCola at dlr.de" <Tomaso.deCola at dlr.de>
Cc:     "edward.greenberg at jpl.nasa.gov" <edward.greenberg at jpl.nasa.gov>, 
"greg.j.kazz at jpl.nasa.gov" <greg.j.kazz at jpl.nasa.gov>, 
"peter.m.shames at jpl.nasa.gov" <peter.m.shames at jpl.nasa.gov>, 
"sls-slp at mailman.ccsds.org" <sls-slp at mailman.ccsds.org>
Date:   05/02/2016 15:39
Subject:        Re: [Sls-slp] CCSDS definition of Protocol IDs

Is there a reason people don?t like:

TFDZ: 3 bits
Reserved: 5 bits
ProtoID: 8 bits
First Header pointer: 16 bits


From: Gian Calzolari <Gian.Paolo.Calzolari at esa.int>
Date: Friday, February 5, 2016 at 8:03 AM
To: "Tomaso.deCola at dlr.de" <Tomaso.deCola at dlr.de>
Cc: Edward Greenberg <edward.greenberg at jpl.nasa.gov>, Greg Kazz <
greg.j.kazz at jpl.nasa.gov>, "Scott, Keith L." <kscott at mitre.org>, Peter 
Shames <peter.m.shames at jpl.nasa.gov>, "sls-slp at mailman.ccsds.org" <
sls-slp at mailman.ccsds.org>
Subject: RE: [Sls-slp] CCSDS definition of Protocol IDs

I think you raised an important point: compactness vs. processing 
complexity. I think that however we should see this trade-off looking at 
the entire Transfer frame data field header, which contains the protocol 
field (s). At the moment it is 32-bit aligned (TFDZ:3 bits, ProtoID: 5 
bits, Extended ProtoID: 8 bits, first header pointer: 16 bits) for a total 
of 32 bits, which is something always desirable. If we reduce the protocol 
IDs from a total of 13 down to 8, the header becomes of 27 bits. If we 
reduce from 13 to 6, it becomes 25 bits. 

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