Network Interface Layer (TCP IP) - buaamer81/IT130-Networking-Wiki GitHub Wiki
Network Interface Layer (TCP/IP Model)
๐ Overview
The Network Interface Layer (also called Link Layer or Network Access Layer) is the lowest layer in the TCP/IP Model.
This layer handles the actual transmission of raw data (frames and bits) over the physical medium (cables, wireless signals, fiber optics).
Think of it as:
โHow is data physically moved across wires, radio waves, or light between devices?โ
๐ง Key Responsibilities
- Frame creation and delivery within the local network (LAN)
- Physical addressing using MAC Address
- Converting data to signals (electrical, light, or radio)
- Access control to the physical medium
- Error detection within the local network
- Managing local communication (within the same LAN segment)
๐ฆ Data Units:
- Frames at Data Link Level
- Bits at Physical Level
๐ Protocols & Standards at Network Interface Layer
| Protocol / Standard | Purpose |
|---|---|
| Ethernet | Most common wired LAN technology |
| Wi-Fi (802.11) | Wireless networking standard |
| PPP (Point-to-Point Protocol) | Serial connections |
| MAC Addressing | Local device identification |
| VLAN (Virtual LAN) | Logical segmentation at Layer 2 |
๐ Devices Operating at Network Interface Layer
| Device | Role |
|---|---|
| Switch | Forwards frames based on MAC Address |
| Hub | Broadcasts all traffic to every port |
| NIC (Network Interface Card) | Interfaces between device and network |
| Access Point | Wireless communication with devices |
๐ง Real-Life Scenario
You connect your laptop to a Wi-Fi network:
- Your NIC (wireless card) sends radio signals (Layer 1).
- Wi-Fi protocol ensures your data frames reach the access point using your device's MAC Address (Layer 2).
๐งช Troubleshooting at Network Interface Layer
| Issue | Possible Cause |
|---|---|
| No connectivity | Bad cable, faulty NIC, unplugged device |
| Collision or interference | Using hubs or crowded wireless channels |
| Frame errors | Cable damage, EMI interference |
| No MAC address response | ARP issues or NIC failure |
Tools to troubleshoot:
- Cable Tester
- Wireshark (frame analysis)
ipconfig /all(Windows)ifconfig(Linux/Mac)
๐ Visual Aids
๐ Related Pages
Return to: TCP/IP Model Overview