Hi,

As from what I understand, Bitcoin nodes transmit transactions twice. First the actual transaction is transmitted; second, the transaction is included in a block and the block is transmitted, effectively transmitting the transaction twice.

The first time a transaction is transmitted, each node verifues the validity of a transaction, before further transmitting it. Again, from what I understand, if the transaction is included in a block, the (all) transaction(s) is (in the block are) verified, before the block is transmitted to the next node.

(Note: these questions are about transaction validity, not the transaction ultimately being accepted in the blockchain)

My questions:
1.a How long does it take to verify the validity of a single transaction (not included in a block)? I guess some assumptions must be made (CPU, memory, number of inouts/outputs in a transaction)
1.b Is there a tool available with which I can test and observe the verification time (of a single and/or multiple transactions)?
2. Is transaction validation of a single transaction (not included in a block) similar to transaction validation of a transaction in a block body?

Thanks.