There is an international standard, though
Consultative Committee for Space Data Systems (CCSDS) Recommended Standard 702.1-B-1 IP Over CCSDS Space Links (https://public.ccsds.org/Pubs/702x1b1c1.pdf)
Supports IPv4 and IPv6 over existing uplink/downlink/crosslink communications protocols. Which SpaceX will have to use if they're not going to roll up their own ground facility network. Existing teleport facilities and COTS use CCSDS protocols.