[Sls-slp] JAXA Response to AOS Pink Sheets

Greg Kazz greg.j.kazz at jpl.nasa.gov
Tue Aug 30 16:03:16 UTC 2005

Dear SLS-SLPers,

Please review the following response from JAXA regarding the proposed 
change to the AOS Space Data Link protocol in terms of extending the frame 
count. Please let me know if you have any comments.



>Date: Tue, 30 Aug 2005 15:52:13 +0900
>From: JAXA CCSDS Secretariat <jaxa.ccsds at jaxa.jp>
>Subject: [CCSDS] Re: More on AOS Pink Sheets
>To: Greg Kazz <Greg.J.Kazz at jpl.nasa.gov>
>  =?ISO-2022-JP?B?GyRCO3ZMMzZJIUsbKEIg?= <taromaru.yoshitaka at jaxa.jp>,
>  JAXA CCSDS <jaxa.ccsds at jaxa.jp>
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>Original-recipient: rfc822;gkazz at mail.jpl.nasa.gov
>Dear Mr. Kazz,
>This is a conclusion from discussions with associates.
>Concerning your response, JAXA cannot agree with your comments, since
>many of JAXA LSIs handle M_PDU production process and AOS transfer frame
>generation process independently.
>Rationale of the proposed change in WG meeting minutes said that the reason
>for this change is due to frame accountability and frame retransmission
>especially for high rate telemetry missions utilizing SLE RCF service.
>JAXA understands that this proposed change is beneficial to frame
>accountability of some high rate telemetry missions.
>But JAXA recognizes that the frame accountability in SLE RCF service is
>achieved by not just "data-link-continuity" parameter (equivalent to VC
>frame count) but also "earth-receive-time" parameter in RCF-TRANSFER-DATA.
>If VC Frame Count remains to provide only 16777216 counts, those information
>seems enough to eliminate ambiguity of frame count during the pass and to
>support frame retransmission needs.
>If those information is not enough for data link frame accountability and VC
>frame count should be augmented for high rate telemetry missions, rather
>than the proposed change, JAXA would prefer the following alternatives;
>1) To define VC Frame Count Extension on spare bits of signaling field in
>AOS Transfer Frame Header as OPTIONAL with an use flag,
>2) To define augmented VC Frame Count in "High Rate AOS Transfer Frame"
>Header having new transfer frame version number (i.e., Version 4).
>Please take this message into your consideration.
>Thank you and best regards,
>I. Nohara
>***  JAXA CCSDS Secretariat       ***
>***   <Phone>  +81 29 868 2613    ***
>***   <Fax>    +81 29 868 2990    ***
>***   <E-Mail> JAXA.CCSDS at jaxa.jp ***

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