[Sis-uce] Thoughts?
Massimilano.Ciccone@esa.int
Massimilano.Ciccone@esa.int
Tue, 13 May 2003 10:23:44 +0100
Hi CFDP folks,
I've carefully read the UCE concept paper and I have the following comments
to make:
I agree with the implementation of a periodic re-examination of the
unfinished transaction upon receipt of EOF(No Error).
I do not agree with issuing a protocol error upon "Check Timer
Expiration". This goes against the nature of CFDP Unacknowledged
procedures, where a Notice of Completion (Completed) is issued upon
reception of an EOF(No Error) PDU, regardless the completeness of the
received file.
I propose NOT to introduce a new error code and to issue a Notice of
Completion(Completed) in any case (also after the Check Timer expired n
times). This would make things much coherent and easier for implementers
(unless there is a precise need in declaring an error in case the received
file is uncomplete)
The use of the "Check Timer" could also be triggered by a flag field in
the header in order to allow backward compatibility with respect to
current CFDP implementations.
Regards
Max
SW Engineer
Data Handling Section
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__________________________________o00-(_)-00o___
Scott Burleigh
<Scott.Burleigh@jpl. To: sis-uce@mailman.ccsds.org
nasa.gov> cc:
Sent by: Subject: [Sis-uce] Thoughts?
sis-uce-admin@mailma
n.ccsds.org
2003/05/12 20:50
Hi, BOF members. I have been supposing that the change described in the UCE
Concept Paper was simple and non-controversial enough to make establishment
of the SIS UCE Working Group rapid and straightforward. Here's where we test
that idea. There seem to be three general points on which we need to reach
rough consensus before we propose WG formation to the Area Director; please
let me know your thoughts on all three.
1. Technical concept.
Is there anything about the technical concept (in the repository at
http://www.ccsds.org/docu/dscgi/ds.py/View/Collection-215) that we need to
revise?
Rob Smith doesn't have funding to participate in the BOF, but he has asked me
to pass this comment along:
"I've just read through your proposed extension to Unacknowledged CFDP to
counter out-of-order delivery. This looks like a very sensible suggestion to
me. However, I feel that 'Check Limit' nomenclature is not the best
description of the (clearly defined) error. 'Check' could describe almost any
of the CFDP faults, e.g. NAK Limit, Positive Acknowledgement Limit, etc. as
they all involve some kind of check.
I think this would be clearer with a more descriptive name, like:
a. Transaction Lifetime Limit
b. Reordering Leeway Limit
c. Unacknowledged Extension Limit
Or some permutation of the above."
I personally think "Check Limit" is okay, but please speak up if you
disagree.
2. Charter.
Is there anything about the Charter (same repository) that is unreasonable?
In particular, would JPL, GSFC, and ESTEC be prepared to provide the
resources to support the necessary demonstrations and interoperability
testing?
3. Working group chair.
When we propose the new Working Group to the Area Director, we need to
identify someone who is willing and able to be its Chair. I will volunteer,
but if anyone else would like to take this on (or nominate some other lucky
BOF member), please feel free!
Scott