What is MSDU, MPDU, PSDU and PPDU in Wi-Fi | Wi-Fi Learning | Video 33 | скачать в хорошем качестве

What is MSDU, MPDU, PSDU and PPDU in Wi-Fi | Wi-Fi Learning | Video 33 |

Welcome to my channel ‪@Insidewifi‬ In Wi-Fi networking, understanding the transition from data to radio waves requires breaking down the four stages of encapsulation. These terms describe the same data as it travels down the OSI Model from the upper layers to the physical antenna. 1. MSDU (MAC Service Data Unit) The MSDU is the "pure payload" that the MAC sublayer receives from the upper layers (like the Network Layer). Analogy: The letter you want to send before it’s put in any envelope. Location: Layer 2 (MAC Sublayer). Key Fact: It consists of the IP packet plus some LLC (Logical Link Control) overhead. 2. MPDU (MAC Protocol Data Unit) When the MAC layer takes the MSDU and wraps it with a MAC Header (containing source/destination addresses) and a Frame Check Sequence (FCS) for error detection, it becomes an MPDU. Analogy: The letter placed inside an addressed envelope. Location: Layer 2 (MAC Sublayer). Key Fact: This is what we commonly refer to as a Wi-Fi Frame. 3. PSDU (PLCP Service Data Unit) The PSDU is technically the exact same thing as the MPDU, but viewed from the perspective of the Physical Layer (PHY). The Handoff: When the MAC layer finishes the MPDU, it hands it down to the Physical Layer. Once the PHY layer receives it, it renames it to "PSDU." Location: Layer 1 (Physical Layer). Key Fact: MPDU = PSDU. The name change simply indicates which layer is currently "handling" the data. 4. PPDU (PLCP Protocol Data Unit) To actually send the PSDU over the air, the Physical Layer adds its own "wrapping." It adds a PHY Preamble (to sync the receiver's radio) and a PLCP Header (containing data rate and transmission length info). Analogy: The addressed envelope placed inside a shipping crate with a barcode for the delivery truck. Location: Layer 1 (Physical Layer). Key Fact: This is the final "packet" that is converted into RF signals and transmitted over the air. msdu, mpdu, psdu, ppdu #msdu #mpdu #psdu #ppdu