Difference between logical and physical address in networking
Logical addresses (IP addresses) are software-assigned, hierarchical, and used for routing data between networks at the Network Layer. Physical addresses (MAC addresses) are hardware-level, burned into NICs, and used for local, node-to-node communication on a LAN. Logical addresses are flexible, while physical addresses are typically permanent.
Key Differences:
- Definition: Logical addresses are virtual/network-level identifiers (e.g., IPv4/IPv6), whereas physical addresses are hardcoded, unique identifiers on a network interface card (e.g., MAC address).
- Layer: Logical addresses operate at Layer 3 (Network Layer) of the OSI model, while physical addresses operate at Layer 2 (Data Link Layer).
- Usage: Logical addresses are used for routing data across different, interconnected networks. Physical addresses ensure accurate delivery within the same local network segment (LAN).
- Flexibility: Logical addresses can change if a device moves to a new network. Physical addresses are permanent and do not change, regardless of the network location.
- Format: IPv4 addresses are 32-bit dotted-decimal, while MAC addresses are 48-bit hexadecimal.
Comparison Table:
| Feature | Logical Address (IP) | Physical Address (MAC) |
|---|---|---|
| Layer | Network Layer (Layer 3) | Data Link Layer (Layer 2) |
| Purpose | Routing between networks | Local delivery within LAN |
| Persistence | Changes based on network | Permanent (hardcoded) |
| Scope | Universal/Global | Local/Network Segment |
| Translation | ARP (Address Resolution Protocol) maps logical to physical | Used directly by switches |
Relationship in Communication:
When a packet is sent, the sender uses the destination logical address to determine the path, but the physical address to deliver the frame to the next immediate device (router or host) in the network path.
