802.11ag MAC Functions ========================= .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the role of the MAC layer in IEEE 802.11a/g?** The MAC layer controls access to the wireless medium, coordinating how devices send and receive data to avoid collisions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does the MAC layer manage medium access?** It uses the Distributed Coordination Function (DCF), a contention-based protocol with CSMA/CA to avoid collisions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is CSMA/CA in 802.11a/g MAC?** Carrier Sense Multiple Access with Collision Avoidance is a mechanism to sense the medium and wait if busy before transmitting. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the Point Coordination Function (PCF)?** PCF is an optional centralized MAC function where the access point controls medium access, providing contention-free service. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does the MAC layer handle acknowledgments?** After a successful frame reception, the receiver sends an ACK frame to confirm delivery, improving reliability. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What are RTS and CTS frames in MAC?** Request to Send (RTS) and Clear to Send (CTS) frames help avoid collisions by reserving the medium before data transmission. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **When does the MAC layer use RTS/CTS?** RTS/CTS is used to reduce collisions, especially for large packets or in environments with hidden nodes. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the backoff algorithm in 802.11a/g MAC?** After detecting a busy medium or collision, devices wait a random backoff time before retrying transmission to avoid repeated collisions. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does the MAC layer ensure fair medium access?** By using contention windows and exponential backoff, it prevents any device from monopolizing the medium. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What are interframe spaces (IFS) in MAC?** Fixed wait times between frame transmissions that prioritize different frame types (e.g., SIFS, DIFS) for orderly communication. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the Short Interframe Space (SIFS)?** SIFS is the shortest wait time used for high-priority frames like ACKs and CTS, minimizing response delay. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the Distributed Interframe Space (DIFS)?** DIFS is a longer wait time used before transmitting new data frames, ensuring higher priority frames get access first. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does the MAC layer handle frame fragmentation?** Large frames can be split into smaller fragments to improve transmission success in noisy environments. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the role of sequence numbers in MAC frames?** They help detect duplicate frames and ensure proper frame ordering. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does the MAC layer handle retransmissions?** If an ACK is not received, the MAC retransmits the frame after a backoff period, improving reliability. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is power management in the MAC layer?** Devices can enter sleep mode and use beacon frames and traffic indication maps to save power while maintaining connectivity. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How are association and authentication handled at the MAC layer?** The MAC layer manages the handshake processes allowing devices to join and authenticate with access points. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is the significance of the MAC address in 802.11a/g?** MAC addresses uniquely identify devices on the wireless network for addressing and communication. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does the MAC layer support QoS (Quality of Service)?** While basic 802.11a/g does not define QoS, extensions like 802.11e enhance MAC to prioritize traffic types. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What challenges does the MAC layer face in 802.11a/g networks?** Challenges include hidden nodes, interference, collisions, and efficient power management. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow Topics in this section, * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`mac_functions Basic Setup on Ubuntu using IPv4 ` * :ref:`Reference links ` .. _mac_functions_step1: .. tab-set:: .. tab-item:: Learnings in this section * In this section, you are going to learn .. _mac_functions_step2: .. tab-set:: .. tab-item:: Terminology * Terminology .. _mac_functions_step3: .. tab-set:: .. tab-item:: Version Info * Version Info .. _mac_functions_step18: .. tab-set:: .. tab-item:: mac_functions Basic Setup on Ubuntu using IPv4 * setup .. _mac_functions_step17: .. tab-set:: .. tab-item:: Reference links * Reference links