Yes very true, but I think this spec came from a scenario setup where all IP-based functionalities were not necessary, i.e. more like protocol encapsulation rather than actual IP operations. And moreover we are talking of a spec published in 2012…
Tomaso Sent from my iPhone > On 28. Feb 2024, at 20:28, Marc Blanchet <marc.blanc...@viagenie.ca> wrote: > > >> Le 28 févr. 2024 à 13:53, Tomaso de Cola via Starlink >> <starlink@lists.bufferbloat.net> a écrit : >> >> But there exists already a CCSDS spec for IP over CCSDS… > > Right, but it is underspecified. It just specifies which value to put in the > frame to identify IP in the payload. It does not talk about how to actually > use IPv6 in such context: neighbor discovery, IP addresses, DAD, … IETF had > made IPv6 over Foo RFCs for that specific matter. Right now, I doubt that two > implementations (if any of IPv6 over CCSDS links exists) would interoperate > with this under spec. > > Marc. > > >> Moreover the snapshot you attached is about TC frames, I.e. for telecommand >> services… >> >> Tomaso >> Sent from my iPhone >> >>>> On 28. Feb 2024, at 18:47, Alexandre Petrescu via Starlink >>>> <starlink@lists.bufferbloat.net> wrote: >>> >>> 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. >>> <example_01.PNG> >>> _______________________________________________ >>> Starlink mailing list >>> Starlink@lists.bufferbloat.net >>> https://lists.bufferbloat.net/listinfo/starlink >> _______________________________________________ >> Starlink mailing list >> Starlink@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/starlink > _______________________________________________ Starlink mailing list Starlink@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/starlink
