[Sls-slp] Encapsulation packets over TC VC Packet service?

John Pietras john.pietras at gst.com
Fri Oct 23 16:55:25 UTC 2020

Dear Gian Paolo.
It’s obvious that I’m due for my annual vision test ☺! I read that line several times and somehow overlooked the “TC (reference [2])”. I am truly embarrassed.

Thank you for your quick response. And to the rest of you, my apologies for wasting your time with  my error.

Best regards,

From: Gian.Paolo.Calzolari at esa.int [mailto:Gian.Paolo.Calzolari at esa.int]
Sent: Friday, October 23, 2020 12:41 PM
To: John Pietras <john.pietras at gst.com>
Cc: sls-slp at mailman.ccsds.org
Subject: Re: [Sls-slp] Encapsulation packets over TC VC Packet service?

Dear John,
        I think that Virtual Channel Packet service of TC (section 3.4 of CCSDS 232.0-B-3) is actually mentioned under the bullet "a" you report below.
That bullet intends to refer to VCP Service that - mutatis mutandis - is actually provided by 3 books:
TM (reference [1]),
TC (reference [2]),
AOS (reference [3]),

Am I overlooking something?


Gian Paolo

From:        "John Pietras" <john.pietras at gst.com<mailto:john.pietras at gst.com>>
To:        "sls-slp at mailman.ccsds.org<mailto:sls-slp at mailman.ccsds.org>" <sls-slp at mailman.ccsds.org<mailto:sls-slp at mailman.ccsds.org>>
Date:        23-10-20 17:27
Subject:        [Sls-slp] Encapsulation packets over TC VC Packet service?
Sent by:        "SLS-SLP" <sls-slp-bounces at mailman.ccsds.org<mailto:sls-slp-bounces at mailman.ccsds.org>>

SLS-SLP colleagues ---

Section of the Encapsulation Packet Protocol Blue Book (CCSDS 133.1-B-3) specifies the content of the SDLP_Channel for the various underlying space data link protocols (SDLPs):

“a)       for the Virtual Channel Packet (VCP) service of TM (reference [1]), TC (reference [2]),

or AOS (reference [3]), SDLP_Channel shall contain the Global Virtual Channel

Identifier (GVCID);

b)         for the MAP Packet (MAPP) service of TC (reference [2]) and USLP (reference [5]),

SDLP_Channel shall contain the Global MAP ID (GMAP ID);

c)         for the Packet Service of Proximity-1 (reference [4]), SDLP_Channel shall contain the

Transfer Frame Version Number, the Spacecraft Identifier (SCID), the Physical

Channel Identifier (PCID), the Data Field Construction ID (DFC_ID), and the Port ID.”

Missing from this list is any mention of the Virtual Channel Packet service of TC (section 3.4 of CCSDS 232.0-B-3. Was this exclusion accidental or intentional – i.e., is Encapsulation over the TC VC Packet service disallowed? I suggest that the issue be resolved unambiguously one way or the other – that is, either add it to the list of SDLP_Channels that contain GVCIDs or add a note that explicitly rules out in that usage.


Best regards,


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