Suggest an editImprove this articleRefine the answer for “What is the data link layer of the OSI model?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**The data link layer (Data Link Layer, L2)** is the second layer of the OSI model, responsible for reliable data transfer between neighboring devices on the same network. **Key point:** the data link layer works with frames and MAC addresses only within a single local network, up to the first router.Shown above the full answer for quick recall.Answer (EN)Image**The data link layer (Data Link Layer, L2)** is the **second layer of the OSI model**, responsible for **reliable data transfer between neighboring devices on the same network**. Put **very simply**: the data link layer solves the task of **"delivering data from one network device to another within a single network segment."** --- ## What the data link layer does The data link layer takes the bit stream from the physical layer and **packages it into frames**, while also making sure it arrives **without corruption**. Main tasks: ### 1. **Framing (building frames)** - data is split into **frames** - service information is added to the data (header and trailer) A frame is the basic "unit of transmission" of the data link layer. --- ### 2. **MAC-level addressing** - every device has a **MAC address** - a frame is sent **from one MAC address to another** The data link layer **does not use IP**, that is a layer above. --- ### 3. **Error control** - a checksum (FCS) is added to the frame - the receiver checks **whether the frame is corrupted** The data link layer usually does not correct errors, it **detects** them. --- ### 4. **Media access control** Answers the question: > who can transmit data, and when Examples: - Ethernet - Wi-Fi (this is especially important there) --- ### 5. **Interaction with the physical layer** - receives bits from below - passes finished frames up (to the network layer) --- ## Where the data link layer operates - within **a single local area network (LAN)** - between **neighboring nodes** - up to the first router It is **not responsible** for anything beyond the network (between different networks). --- ## Data link layer devices - **switches** - network interface cards (NIC) They work with: - frames - MAC addresses --- ## Simple analogy Office mail: - an envelope with the recipient's name is the **frame** - the name on the envelope is the **MAC address** - delivery inside the building is the **data link layer** --- ## Short definition for an interview > **The OSI data link layer** delivers data as frames between devices on the same network, using MAC addresses and performing error control and media access control.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.