Need for IP addressing in a Network

  • In a local network (without internet), devices can sometimes communicate without IP, using protocols like Bluetooth or Ethernet with MAC addresses (e.g. Layer 2 communication).

  • But on the internet, an IP address is essential—it’s the core system that allows devices to be found and communicate across networks.

Local Network: Can Work Without IP (In Some Cases)?

  • Yes, a local network (like within a home or office) can work without IP addresses — but only for certain types of communication at Layer 2 (Data Link Layer).
  • Devices can communicate using MAC addresses, and protocols like:
    • Ethernet frame exchange
    • ARP (Address Resolution Protocol)
    • LLDP, CDP (device discovery)
    • Some file sharing or printing protocols (via broadcast or multicast)

Note: Most local networks do not work without an IP address in the local network.

Limitations:

  • No IP = no TCP/IP = no internet, no web, no modern apps.
  • Works for very basic device-to-device discovery or low-level functions only.

Global Network (Internet): Cannot Work Without IP?

  • The internet is built on IP (Internet Protocol).
  • Every device must have an IP address (public or translated via NAT) to send/receive data globally.
  • No IP = No internet access.

Even things like:

  • Web browsing
  • Email
  • Video streaming
  • Cloud services

All require IP addresses to route data correctly over the internet.

 Final Summary

Network Type Can It Work Without IP? Why / Why Not
Local Network ✅ Yes, in limited cases Layer 2 protocols (like MAC-based Ethernet) still work
Global Network ❌ No IP is essential for routing and identifying devices

1. Devices That Assign IPs in a Local Network (Without Internet)

Device / Method Why It’s Used
Router (without internet) Assigns local IPs via DHCP even without internet.
PC with DHCP Server Software Acts as a DHCP server when no router is present.
Dedicated DHCP Server Used in larger LANs to manage IPs centrally.
Manual Configuration (Static IP) Manually sets IPs when DHCP isn’t used.
Switch (only if Layer 3 + DHCP relay) Forwards DHCP requests to DHCP server, not assign IPs itself.

2. Devices/Systems That Assign IPs Over the Internet

Device / System Why It’s Used
ISP (Internet Service Provider) Assigns public IPs to customer routers for internet access.
Cloud Providers (AWS, Azure, etc.) Assign public or private IPs to cloud VMs/services.
Carrier-Grade NAT (by ISP) Shares one public IP among many users using internal mapping.

3. Devices That Assign IPs for Both Local Network & Internet

Device / System Why It’s Used
Router (Home/Office) Assigns private IPs locally and uses public IP from ISP for internet.
Mobile Hotspot (Phone) Acts as DHCP server for connected devices and uses mobile data for internet.
Modem-Router Combo Handles both internet access and local IP assignment.