Suggest an editImprove this articleRefine the answer for “How does the data link layer differ from the physical layer?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**The data link layer and the physical layer solve different tasks**: the physical layer transmits bits as a signal, while the data link layer works with frames and addresses inside the network. **Key point:** the data link layer knows frame boundaries, uses MAC addresses, and detects errors (FCS), while the physical layer does none of that.Shown above the full answer for quick recall.Answer (EN)Image**The data link layer and the physical layer solve different tasks**, even though they work side by side. The main difference: **the physical layer transmits bits as a signal**, while **the data link layer works with frames and addresses inside the network**. --- ## Key differences in simple terms ### 1. **What they work with** - **Physical layer (L1)** Works with **bits (0 and 1)** and signals: voltage, light, radio waves - **Data link layer (L2)** Works with **frames**: structured data with MAC addresses --- ### 2. **Understanding data** - **L1**: does not understand the data structure does not know where a message starts and ends - **L2**: knows the frame boundaries understands who the data is intended for (MAC) --- ### 3. **Addressing** - **Physical layer** does not use addresses - **Data link layer** uses **MAC addresses** --- ### 4. **Error control** - **L1** does not check for errors - **L2** detects errors (FCS) --- ### 5. **Area of responsibility** - **Physical layer** "How to transmit the signal" - **Data link layer** "Whom to deliver the data to, and in what form, inside the network" --- ## Comparison table | Characteristic | Physical (L1) | Data link (L2) | |---|---|---| | Unit of data | Bit | Frame | | Addressing | None | MAC address | | Error control | None | Yes | | Type of data | Signals | Structured data | | Devices | Cable, repeater | Switch, NIC | --- ## Simple analogy Road and mail: - **Physical layer** - the road - **Data link layer** - delivering packages with addresses within the city --- ## Short answer for an interview > **The physical layer transmits bits as signals**, while **the data link layer builds frames, uses MAC addresses, and delivers data within a single network**.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.