[SIS-CFDPV1] Multiple file delivery request in a single Metada PDU and compressed delivery....

[Tomaso.deCola at dlr.de]

Hi Cheol,

My understanding of CFDP is that it’s transaction based, where a transaction is aimed at transferring a single file. As such, transmission of multiple files has to go over different transactions. Moreover, the metadata allow to specify a single file name (source and destination) so that the possibility of sending multiple files with the same put request does not seem to me possible.
As to the compression, in my opinion this is something that can happen outside the CFDP operations.

Regards,

Tomaso

From: SIS-CFDPV1 <sis-cfdpv1-bounces at mailman.ccsds.org> On Behalf Of ??? via SIS-CFDPV1
Sent: Mittwoch, 7. Dezember 2022 01:49
To: sis-cfdpv1 at mailman.ccsds.org
Subject: [SIS-CFDPV1] Multiple file delivery request in a single Metada PDU and compressed delivery....

Hi, CFDP fellow.

Recently, I am questioning to myself about how I am able to get multiple files from remote space storage through CFDP.
In the current CFDPv1 specification, we have to send multiple put.request commands to a sending entity as many as needed.

Is it possible to think putting multiple file source in a metadata pdu and also possibly compressed by tar, zlib and so on to make it possible?
For example, we can compile a metadata pdu as follows when a sending CFDP entity got requests for the aaa.txt bbb.tlm, ccc.img, ddd.dat separately:
File size : file size of compressed file, i.e., size of measurement_data.gz
Source file name : aaa.txt bbb.tlm, ccc.img, ddd.dat
Destination file name : measurement_data.gz

In my opinion, voluntary compression service by a sending CFDP entity would be good in terms of bandwidth reduction, lower retransmission rate and so on.

Cheol


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