it places a new MAC header on the data packet. The new MAC header contains the destination MAC address of router 2, and the MAC address of the first router becomes the new source MAC. The IP header remains unchanged. The first router passes the data packet through the port that it selects and on to subnetwork 5. The data passes along subnetwork 5. The data packet continues along subnetwork 5 until it reaches router 3. Like the other devices on subnetwork 5, router 3 sees the data packet. This time it picks it up because it recognizes that its own MAC address is the same as the destination MAC address.At the data link layer, the router strips off the MAC header, and passes it up to the network layer. There, it sees that the destination IP address in the IP header matches that of a host that is located on one of the subnetworks to which it is attached. Next, the router determines that it must send the data packet through whichever one of its ports is attached to subnetwork 8, in order for the data packet to reach its destination address. It places a new MAC header on the data. This time, the new MAC header contains the destination MAC address of host Z, and the source MAC address of router 3. As before, the IP header remains unchanged. Router 3 sends the data through the port that is attached to subnetwork 8.The data packet travels along subnetwork 8. All hosts that it passes by, examine it, but do not copy it, when they see that the destination MAC address carried by the MAC header does not match their own. Finally, it reaches host Z, which picks it up because it sees that its MAC address matches the destination MAC address carried in the MAC header of the data packet. Host Z strips off the MAC header and passes the data to the network layer. At the network layer, host Z sees that its IP address, and the destination IP address carried in the IP header, match. Host Z strips off the IP header and passes the data up to the transport layer ...
