How do I know what node is broadcasting my transaction to the network? how can i get more information about this node? for example, how do i know if the node is a geth or parity node? does it matter?
You're missing the blockchain concept.
Transactions are processed on all nodes. Mining determines the order of the transactions all nodes eventually agree on. This is not the same thing as a node running transactions and the rest of the network accepting its findings.
My answer over here may shed some more light on this. how blockchain can handle the concurrency?
Hope it helps.