The access method is CSMA/CD - carrier sense multiple access with collision detect.
data link layer
tracert, traceroute
Use tracert to see where your packets are being dropped.
router's
This is known as "stateful" filtering - When firewalls are aware of the traffic state as well as the content of the packets.
Packets Words
To determine a method of encapsulating data and transport packets between two devices in a network
You need a protocol analyzer or a packet sniffer. They will capture packets and attempt to analyze them for proper protocol.
a. Multimeter
tunneling
Packets
The network layer is the layer that is responsible for routing packets on the network. This is the layer in which Internet protocol operates. In the seven layer OSI model, the network layer is the third layer from the bottom.