The CCSDS spec is an interesting document.
I am trying to find a packet dump of a CCSDS packet that travelled in
space according to this CCSDS spec. If there is a place with CCSDS
packet dumps I am interested to see them.
Given that, I could think about writing an IPv6-over-CCSDS preliminary
Internet Draft.
I could find a png image of a packet dump at ESA
(https://essr.esa.int/project/ccsds-wireshark-dissector), but that is
not a real packet dump binary file that could be loaded in wireshark;
strangely, they do provide a dissector, but not a packet.
Here are my IPv6 comments about CCSDS, relative to that png of a CCSDS
packet (png attached):
- the shown 'Frame Length' field is on 16bits. For IPv6, this can be
fine, in principle. The good thing is that the minimum MTU of IPv6 is
1280, and that can be encoded ok with a 16bit length field. On
another hand, the 'Payload Length' of IPv6 is also on 16bit. This
means that the largest normal IPv6 packet would not fit into a single
CCSDS frame, and would need to be fragmented by CCSDS. Maybe
fragmentation is little desirable when RTT is 45minutes. And, there
are also the IPv6 'jumbograms'.
- there is a 'Spacecraft ID' and 'VC ID' fields combined on 16bits:
this field could be used, if appropriate in some context, to help with
forming IPv6 link-local addresses. If there is worry about privacy,
and these IDs could be used to input hashes, such as to obtain
hopefully unique numbers; these hopefully unique numbers are often
necessary when designing IPv6 addressing architectures, subnet
numbers, IPv6 ULA addresses, secure addresses for secure
identification, and similar.
- there is a 'SDLS Header' containing a 'Security Parameter Index'
field. If this packet contains an IPv6 packet with an ESP header
(encapsulated sec'y protocol) then that too has a 'Security Parameter
Index' field (SPI). It would be good to re-use. Ideally, one would
rely entirely on IPsec and almost not at all on CCSDS-specific security.
Alex
Le 23/02/2024 à 19:03, Dave Taht via Starlink a écrit :
Given the trouble the moon lander has had communicating, I looked over
this just now.
https://public.ccsds.org/Pubs/133x0b2e1.pdf
I reviewed a similar document for the earth-moon corridor by NASA
about 2 years ago, and it was a mess of non-interoperable bands and
protocols. I cannot remember the name of that one.
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