Ip-Address

Overview A MAC address is a hardware identifier burned into a network interface card and used to move frames across a single local link. An IP address is a logical network address assigned to a device and used to route packets across interconnected networks, including the internet. They operate at different OSI layers, working together to get data from one physical wire to a destination anywhere in the world. Comparison Diagram Host AIP 10.0.0.5Routerrewrites MAC per hopHost BIP 10.0.0.9MAC AA:01 to MAC RR:01MAC RR:02 to MAC BB:01Layer 2 - MAC changes at every hopIP 10.0.0.5 to 10.0.0.9Layer 3 - IP stays constant end-to-endMAC = local hop identity; IP = end-to-end address Comparison Table Aspect MAC Address IP Address OSI layer Layer 2 (Data Link) Layer 3 (Network) Format 48-bit hex, e.g. 00:1A:2B:3C:4D:5E 32-bit (IPv4) or 128-bit (IPv6) dotted/colon notation Assignment Burned in by the NIC manufacturer at production Assigned by a network admin or DHCP server Structure Flat, no hierarchy — vendor prefix plus serial Hierarchical — network portion plus host portion for routing Persistence Fixed to the physical interface (though spoofable) Can change when a device moves to a different network Role in delivery Identifies the next-hop device on the local link Identifies source and destination across the whole path Behavior across hops Rewritten by every router at each hop Preserved end-to-end (barring NAT) Resolution mechanism Discovered via ARP (IPv4) or NDP (IPv6) Discovered via DNS for hostnames Key Differences MAC address operates at Layer 2 while IP address operates at Layer 3. MAC is burned into hardware by the manufacturer, whereas IP is assigned by the network. A frame’s MAC addresses are rewritten at every hop, but the packet’s IP addresses stay end-to-end constant. ARP maps an IP address to the MAC address needed for delivery on the local segment. MAC addresses are flat with no structure, while IP addresses are hierarchical to support routing. When to Use Each MAC Address ...