earches its routing tables in order to map a route, for the network address of the destination, to the MAC address of the router that is connected to subnetwork 8. The router is using RIP as its routing protocol, therefore, it determines that the best path for the data is one that places the destination only three hops away. Next, the router determines that it must send the data packet through whichever one of its ports is attached to subnetwork 4, in order for the data packet to reach its destination via the selected path. The router passes the data down to the data link layer, where 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 that became the new source. The IP header remains unchanged. The first router passes the data packet through the port that it selects, and on to subnetwork 4. The data passes along subnetwork 4. 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. The data packet continues along subnetwork 4 until it reaches router 2. Like the other devices on subnetwork 4, the router 2 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 the data up to the network layer. There, it examines the destination network IP address, and looks in its routing table. The router, using RIP as its routing protocol, determines that the best path for the data is one that places the destination only two hops away. Next, the router determines that it must send the data packet through whichever one of its ports is attached to subnetwork 5, in order for the data packet to reach its destination via the selected path. The router passes the data down to the data link layer where ...
