<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=Windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; color: rgb(0, 0, 0); font-size: 20px; font-family: Calibri, sans-serif; "><div>Dear SLS-SLP WG,</div><div><br></div><div>Below please find comments from Gian Paolo on Prox-1 Data Link Section 5 Timing Services. We will be reviewing the entire Prox-1 Data Link Layer book during our Berlin meeting including this section as well.</div><div>Please let me know if you have any responses to these comments below</div><div><br></div><div>Thanks and best regards,</div><div><br></div><div>Greg Kazz</div><div>Chairman SLS-SLP WG</div><div><br></div><span id="OLK_SRC_BODY_SECTION"><div style="font-family:Calibri; font-size:11pt; text-align:left; color:black; BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 0in; PADDING-RIGHT: 0in; BORDER-TOP: #b5c4df 1pt solid; BORDER-RIGHT: medium none; PADDING-TOP: 3pt"><span style="font-weight:bold">From: </span> "<a href="mailto:Gian.Paolo.Calzolari@esa.int">Gian.Paolo.Calzolari@esa.int</a>" <<a href="mailto:Gian.Paolo.Calzolari@esa.int">Gian.Paolo.Calzolari@esa.int</a>><br><span style="font-weight:bold">Date: </span> Tue, 3 May 2011 07:57:20 -0700<br><span style="font-weight:bold">To: </span> "Kazz, Greg J (313B)" <<a href="mailto:greg.j.kazz@jpl.nasa.gov">greg.j.kazz@jpl.nasa.gov</a>><br><span style="font-weight:bold">Cc: </span> Marjorie de Lande Long <<a href="mailto:marjorie@delandelong.com">marjorie@delandelong.com</a>><br><span style="font-weight:bold">Subject: </span> Proximity-1 Timing Services<br></div><div><br></div><br><font size="2" face="sans-serif">Greg,</font><br><font size="2" face="sans-serif"> As
you know the current CCSDS 211.0-B-4 July 2006 Proximity-1 DLL Blue Book
contains a Section 5 titled PROXIMITY-1 TIMING SERVICES containing two
subsections: 5.1 COUPLED NON-COHERENT PROXIMITY TIMING SERVICE and 5.2
PROXIMITY TIME CORRELATION.</font><br><font size="2" face="sans-serif">Comparing the blue book in force with
your latest file “CCSDS_211.0-B-4_Apr20_2011_GJK.doc” there are no changes
apart from a typo (course --> coarse).</font><br><br><font size="2" face="sans-serif">I think this section deserves some clarification
despite we are doing a good work with the clarifications that will go into
the Proximity-1 C&S Book.</font><br><font size="2" face="sans-serif">See the items below.</font><br><br><font size="2" face="sans-serif">Regards</font><br><br><font size="2" face="sans-serif">Gian Paolo</font><br><br><font size="2" face="sans-serif">---------------------------</font><br><font size="2" face="sans-serif">#1</font><br><font size="2" face="sans-serif">I think that clause 5.1.1 is not really
a normative clause (it says: Timing Services are required for Proximity
operations in order to provide the following three capabilities........)
but just an informative preamble. There is no "shall formulation"
and no one of the 3 listed capabilities is "fully" specified
in the document.</font><br><font size="2" face="sans-serif">The same could be said for clause 5.1.2
(it says: </font><font size="3" face="Times New Roman">All three of these
capabilities require that </font><font size="2" face="Times New Roman">MODE</font><font size="3" face="Times New Roman">is <i>active </i>and</font><font size="2" face="sans-serif">.....)
as I think that requirements on the MODE setting are elsewhere.</font><br><font size="2" face="sans-serif">Recommendation: transform section 5.1
into a non normative section titled e.g. OVERVIEW.</font><br><font size="2" face="sans-serif">---------------------------</font><br><font size="2" face="sans-serif">#2</font><br><font size="2" face="sans-serif">Following the suggestion #1 above, the
current section 5.2.1 OVERVIEW could be embedded into 5.1 as it continues
the description.</font><br><font size="2" face="sans-serif">---------------------------</font><br><font size="2" face="sans-serif">#3</font><br><font size="2" face="sans-serif">The first sentence of 5.2.1 OVERVIEW
(i.e.: "The method requires that both the initiating and recipient
transceiver shall have the capability of time tagging the trailing edge
of the last bit of the Attached Synchronization Marker of every incoming
and every outgoing Proximity frame.") should be modified removing
"shall" (i.e. From " transceiver shall have" To "
transceiver have".</font><br><font size="2" face="sans-serif">In fact shall can only be in normative
sections.</font><br><font size="2" face="sans-serif">---------------------------</font><br><font size="2" face="sans-serif">#4</font><br><font size="2" face="sans-serif">Steps a) to c) in in 5.2.2 TIME TAG
CAPTURE METHOD are fine with me.</font><br><font size="2" face="sans-serif">Step d) is unverifiable and not fully
specified in this document.</font><br><font size="2" face="sans-serif">The "Proximity time correlation
packet" is undefined in this document (despite it deserves also an
acronym TCP).</font><br><font size="2" face="sans-serif">The processing of "Proximity time
correlation packet" is undefined in this document.</font><br><font size="2" face="sans-serif">Recommendation: convert step d) into
descriptive statements specifying that the further processing is not defined
in this document.</font><br><font size="2" face="sans-serif">---------------------------</font><br><font size="2" face="sans-serif">#5</font><br><font size="2" face="sans-serif">Remove from Annex E the acronym TCP
= Time Correlation Packet</font><br><font size="2" face="sans-serif">It is never used.</font><br><font size="2" face="sans-serif">It is likely to create confusion with
e.g. TCP/IP if used.</font><br><font size="2" face="sans-serif">---------------------------</font><br><br></span></body></html>