Proposal for a dataformat for communication between groundstations and their connected computers

Basically what I was thinking about was mostly the tracking of things, but I wanted to build a protocol in a way that the groundstations stay compatible for a deployment stage that enables them to send. This will surely not be the case for a while but still i'd like to think ahead. The main idea was that this kind of frame can be received and sent to the groundstation. For communication among groundstations over a satellite at least some kind of from adress field needs to be added.

Dataformat

Position	Length	Name	Meaning
0	32	magic	magic id = 2 bytes, 'HGG!'
4	64	rcpnt	hardware adress of the receipient
12	16	protocol	protocol to be used in the payload
14	16	size	size of payload
16	32	chksum	checksum of payload (??)
20	16	modno	the receiving module that has generated this request
22	n	payload	payload goes here, variable size

No idea if a magic would be really needed. Basically it's a simple frame format that can be used to implement sending and receiving with the groundstations and should thus be capable of handling different stages in the project. The frames can bei either sent over a serial cable or other device types (like ethernet, firewire or anything else) but still allows to control hardware inside the groundstation directly.

Hardware Adresses

Since we want to have a distributed network, we also need to think about how to send something over several hops and look into routing strategies in p2p networks. Knowledge about p2p networks and their protocol design is needed for this. I've been imagining a hardware adress based on the groundstation position and some random component - no idea if that'll work.

Protocols

Here are a few possibilities

0 = Tracking (from = 0, rcpnt = own hw id)
1 = hardware ping (for finding out about other groundstations)
2 = groundstation diagnostics and control options
128 = Networking (Ethernet Frames go here)
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