MAC_C, MAC_D, 192.168.2.2, 192.168.1.2
The HCIA-Datacom training material explains that routers forward packets based on destination IP addresses while changing the data-link encapsulation at each hop.
When PC2 sends data to PC1, the source IP address is 192.168.2.2 and the destination IP address is 192.168.1.2.
These IP addresses remain unchanged as the packet travels across R2 and R1 during conventional routing.
However, the Ethernet source and destination MAC addresses are replaced at each routing hop.
When R2 forwards the packet toward R1, it uses its outgoing interface MAC address, MAC_D, as the source MAC address.
The destination MAC address is MAC_C, which belongs to R1 ' s interface connected to R2.
Therefore, the packet forwarded from R2 contains destination MAC MAC_C, source MAC MAC_D, source IP 192.168.2.2, and destination IP 192.168.1.2.
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