As the routers are only involved with the process of finding the best route to reach an IP address (the destination hosts), they don't look at the IP Datagram payload (which includes the transport protocol header), only to IP header.
So, the only transport processes that "talk"each other, are the one on the source host (defining TCP or UDP source port/s, and the other on the destination host (defining TCP or UDP destination port/s), so two applications (or more) in both machines can exchange data.
Data validation means to check the quality and accuracy of input data before processing. It ensures that the source data's quality is good enough and it is able to process.
No, it's not, when a virus blocks a file stored in a sandbox, it does not affect the system.
However, the virus program does not necessarily recognize other parts of the program. It still takes analysis to determine what. Also, the virus vault must be emptied to delete the original files
