802.11b ============ .. toctree:: :maxdepth: 1 :hidden: :includehidden: 802_11b/802_11b 802_11b/mac_functions 802_11b/mac_timings 802_11b/packet_formats 802_11b/power_save 802_11b/interoperability 802_11b/physical_rates 802_11b/ppdu IEEE 802.11b is a Wi-Fi standard that operates in the 2.4 GHz band and supports data rates up to 11 Mbps using DSSS modulation. .. list-table:: :widths: 20 60 20 :header-rows: 1 * - Category - Description - Use Case * - MAC Functions - Core MAC layer responsibilities like frame delimiting, addressing, error checking. - Managing wireless communication and reliable data delivery * - MAC Timings - Timing parameters like SIFS, DIFS, backoff timers controlling transmission. - Coordination of medium access and collision avoidance * - Packet Formats - Structure of 802.11b frames including header, payload, and control frames. - Frame parsing and network management * - Power Save - Power saving mechanisms allowing devices to enter low power modes. - Extending battery life while maintaining connectivity * - Interoperability - Mechanisms for compatibility with other 802.11 standards and vendors. - Seamless multi-vendor and multi-standard network operation * - Physical Rates - Supported data rates and modulation schemes of 802.11b, including DSSS and CCK up to 11 Mbps. - Flexible throughput options in 2.4 GHz band with robust legacy support * - PPDU - Physical Protocol Data Unit format including preamble and data fields using DSSS/CCK. - Synchronization and reliable data transmission in 2.4 GHz Wi-Fi .. tab-set:: .. tab-item:: 802.11b MAC Functions **Standard:** IEEE 802.11b (1999) **Main Features:** - Responsible for frame delimiting, addressing, and error detection - Handles reliable wireless communication and retransmissions - Manages access to the shared wireless medium (CSMA/CA) - Controls acknowledgments (ACK) and retransmission of lost frames - Supports fragmentation and reassembly of frames - Works closely with the Physical Layer to enable wireless connectivity **Use Cases:** - Ensuring reliable data delivery over 2.4 GHz Wi-Fi networks - Managing wireless medium access in WLANs - Supporting QoS and security through frame management **Related Functions:** - Frame control and addressing schemes - Sequence control for packet ordering - Power management signaling - Error detection using CRC .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Explore the details of 802.11b MAC Functions:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`mac_functions Basic Setup on Ubuntu using IPv4 ` * :ref:`Reference links ` .. button-link:: ./802_11b/mac_functions.html :color: primary :shadow: :expand: Jump to "802.11b MAC Functions" .. tab-set:: .. tab-item:: 802.11b MAC Timings **Standard:** IEEE 802.11b (1999) **Main Features:** - Defines timing parameters for frame transmission and acknowledgments - Includes Interframe Spaces (SIFS, DIFS, PIFS) to coordinate access - Specifies slot times and contention window for CSMA/CA backoff - Ensures collision avoidance and fair medium access - Manages timing for retransmissions and acknowledgments - Synchronizes MAC and PHY layers for efficient wireless communication **Use Cases:** - Coordinating transmission timing in 2.4 GHz WLANs - Reducing collisions and optimizing throughput - Supporting Quality of Service (QoS) through prioritized timing **Related Timing Parameters:** - Short Interframe Space (SIFS) - Distributed Interframe Space (DIFS) - Arbitration Interframe Space (AIFS) - Slot time and backoff timers .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Explore the details of 802.11b MAC Timings:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`mac_timings Basic Setup on Ubuntu using IPv4 ` * :ref:`Reference links ` .. button-link:: ./802_11b/mac_timings.html :color: primary :shadow: :expand: Jump to "802.11b MAC Timings" .. tab-set:: .. tab-item:: 802.11b Packet Formats **Standard:** IEEE 802.11b (1999) **Main Features:** - Defines the structure of MAC and PHY layer frames used in 802.11b - Includes Frame Control, Duration, Address fields, Sequence Control, and CRC - Supports data frames, management frames, and control frames - Uses DSSS (Direct Sequence Spread Spectrum) or CCK modulation at the PHY layer - Frame formats support addressing, QoS, and security features - Allows fragmentation and reassembly for large packets **Use Cases:** - Structuring wireless packets for communication in 2.4 GHz WLANs - Ensuring proper delivery, acknowledgment, and retransmission of data - Enabling interoperability between devices by standardized frame formats **Related Frame Types:** - Management frames (e.g., Beacon, Probe Request) - Control frames (e.g., ACK, RTS, CTS) - Data frames (with or without QoS) .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Explore the details of 802.11b Packet Formats:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`packet_formats Basic Setup on Ubuntu using IPv4 ` * :ref:`Reference links ` .. button-link:: ./802_11b/packet_formats.html :color: primary :shadow: :expand: Jump to "802.11b Packet Formats" .. tab-set:: .. tab-item:: 802.11b Power Saving Mechanisms **Standard:** IEEE 802.11b (1999) **Main Features:** - Supports Power Save Mode (PSM) to reduce energy consumption on client devices - Clients enter a low-power sleep state and wake periodically to receive buffered data - Access Point buffers frames for sleeping stations and indicates buffered data in beacon frames - Uses Delivery Traffic Indication Message (DTIM) to inform clients about multicast/broadcast data - Enables efficient battery usage for mobile and portable Wi-Fi devices operating in 2.4 GHz band - Coordinates sleep and wake cycles with MAC layer signaling mechanisms **Use Cases:** - Extending battery life of Wi-Fi enabled mobile devices on 2.4 GHz networks - Reducing power consumption in IoT and embedded Wi-Fi devices - Balancing wireless network performance with power efficiency **Related Mechanisms:** - Beacon frame scheduling - DTIM and TIM fields for power management - Client wake-up and sleep signaling .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Explore the details of 802.11b Power Saving mechanisms:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`power_save Basic Setup on Ubuntu using IPv4 ` * :ref:`Reference links ` .. button-link:: ./802_11b/power_save.html :color: primary :shadow: :expand: Jump to "802.11b Power Saving" .. tab-set:: .. tab-item:: 802.11b Interoperability **Standard:** IEEE 802.11b (1999) **Main Features:** - Ensures compatibility between devices from different vendors using 2.4 GHz band - Supports backward compatibility with legacy 802.11 standards (e.g., 802.11) - Defines common frame formats and signaling to facilitate seamless communication - Implements clear channel assessment (CCA) and CSMA/CA for medium access coordination - Uses standardized management and control frames for association and roaming - Facilitates coexistence with other wireless technologies in the crowded 2.4 GHz band **Use Cases:** - Enabling multi-vendor Wi-Fi deployments in consumer and enterprise 2.4 GHz networks - Supporting seamless handoff and roaming in heterogeneous Wi-Fi environments - Allowing mixed 802.11 standard networks to operate without interference **Related Mechanisms:** - Management frame interoperability - Frequency band coordination and interference management - Standardized PHY and MAC layer procedures .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Explore the details of 802.11b Interoperability mechanisms:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`interoperability Basic Setup on Ubuntu using IPv4 ` * :ref:`Reference links ` .. button-link:: ./802_11b/interoperability.html :color: primary :shadow: :expand: Jump to "802.11b Interoperability" .. tab-set:: .. tab-item:: 802.11b Physical Rates **Standard:** IEEE 802.11b (1999) **Main Features:** - Supports physical layer data rates of 1, 2, 5.5, and 11 Mbps - Utilizes Direct Sequence Spread Spectrum (DSSS) modulation - Operates exclusively in the 2.4 GHz ISM frequency band - Provides backward compatibility with original 802.11 (1 and 2 Mbps rates) - Uses adaptive rate selection based on signal quality - Employs 22 MHz channel bandwidth typical for 2.4 GHz band **Use Cases:** - Wireless connectivity in home and small office environments - Basic internet browsing and email over Wi-Fi - Supporting legacy devices in mixed 802.11 networks **Related Concepts:** - Rate adaptation mechanisms - DSSS modulation and spreading codes - Interference management in crowded 2.4 GHz band .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Explore the details of 802.11b Physical Rates:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`physical_rates Basic Setup on Ubuntu using IPv4 ` * :ref:`Reference links ` .. button-link:: ./802_11b/physical_rates.html :color: primary :shadow: :expand: Jump to "802.11b Physical Rates" .. tab-set:: .. tab-item:: 802.11b PPDU **Standard:** IEEE 802.11b (1999) **Main Features:** - Defines the Physical Protocol Data Unit (PPDU) structure for 802.11b - Includes a synchronization preamble and header for timing and channel estimation - Contains SIGNAL field specifying data rate and frame length - Payload carries MAC frames modulated using DSSS - Supports multiple data rates with adaptive rate selection - Enables reliable wireless data transmission in the 2.4 GHz band **Use Cases:** - Ensuring proper encapsulation and transmission of data over 802.11b PHY - Synchronization between wireless transmitters and receivers - Facilitating stable and efficient communication in legacy Wi-Fi networks **Related Concepts:** - DSSS symbol structure and spreading codes - Service field and error correction bits - Channel coding and interleaving techniques .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Explore the details of 802.11b PPDU:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`ppdu Basic Setup on Ubuntu using IPv4 ` * :ref:`Reference links ` .. button-link:: ./802_11b/ppdu.html :color: primary :shadow: :expand: Jump to "802.11b PPDU"