GSM - Global System for Mobile Communications (2G) ======================================================= .. 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 GSM?** * GSM (Global System for Mobile Communications) is a standard developed to describe protocols for second-generation (2G) digital cellular networks. It enables voice calls, SMS, and limited data services using circuit-switched technology. * GSM defines how mobile phones communicate with base stations and the core network using a layered protocol stack. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Why is GSM useful?** * GSM revolutionized mobile communication by offering: * Global interoperability – Used in over 200 countries. * Secure voice and text – With built-in encryption and authentication. * Efficient spectrum use – Through TDMA and frequency reuse. * Roaming support – Seamless service across networks and countries. * Foundation for 2G/3G/4G evolution – GSM laid the groundwork for modern mobile networks. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How it works?** * Mobile Registration – The phone connects to the nearest base station and authenticates with the network. * Call Setup – The MSC (Mobile Switching Center) routes the call using signaling protocols. * Voice/Data Transmission – Voice is digitized, encrypted, and transmitted over the air. * Call Termination – The session ends and resources are released. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Where is GSM used?** * 2G mobile networks – For voice and SMS. * M2M/IoT devices – In low-bandwidth applications. * Fallback for newer networks – When 3G/4G/5G is unavailable. * Rural and legacy systems – Where modern infrastructure is limited. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Which OSI layer does GSM belong to?** * GSM spans multiple OSI layers, but its core signaling and control functions are implemented at Layer 2 and Layer 3. Here's why: * Layer 2 (Data Link Layer): GSM uses LAPDm (Link Access Protocol on the Dm channel) for reliable communication between the mobile and BTS. * Layer 3 (Network Layer): GSM signaling protocols like RR (Radio Resource), MM (Mobility Management), and CM (Call Control) operate here to manage sessions, mobility,and call setup. * Layer 1 (Physical Layer): Handles radio transmission using TDMA and frequency hopping. .. 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:`GSM Version&RFC Details ` * :ref:`GSM Basic Setup on Ubuntu using IPv4 ` * :ref:`GSM Basic Setup on Ubuntu using IPv6 ` * :ref:`GSM Protocol Packet Details ` * :ref:`GSM Usecases ` * :ref:`GSM Basic Features ` * :ref:`GSM Feature : Digital Voice Transmission ` * :ref:`GSM Feature : SIM-Based Authentication ` * :ref:`GSM Feature : International Roaming ` * :ref:`GSM Feature : SMS Support ` * :ref:`GSM Feature : Call and Message Encryption ` * :ref:`GSM Feature : Supplementary Services ` * :ref:`GSM Feature : Efficient Spectrum Usage ` * :ref:`GSM Feature : Low Power Consumption ` * :ref:`GSM Feature : Emergency Calling ` * :ref:`GSM Feature : Support for Data Services ` * :ref:`Reference links ` .. _GSM_step1: .. tab-set:: .. tab-item:: Learnings in this section * In this section, you are going to learn .. _GSM_step2: .. tab-set:: .. tab-item:: Terminology * Terminology .. _GSM_step3: .. tab-set:: .. tab-item:: Version Info * Version Info .. _GSM_step5: .. tab-set:: .. tab-item:: GSM Version&RFC Details .. csv-table:: :file: ./GSM/GSM_rfc_details.csv :widths: 10,10,10,30 :header-rows: 1 .. _GSM_step20: .. tab-set:: .. tab-item:: GSM Basic Setup on Ubuntu using IPv4 * Setup .. _GSM_step21: .. tab-set:: .. tab-item:: GSM Basic Setup on Ubuntu using IPv6 * Setup .. _GSM_step6: .. tab-set:: .. tab-item:: GSM Protocol Packet Details **RR (Radio Resource) Setup Packet** .. csv-table:: :file: ./GSM/GSM_packet1_details.csv :widths: 10,20,30,10 :header-rows: 1 **MM (Mobility Management) Packet** .. csv-table:: :file: ./GSM/GSM_packet2_details.csv :widths: 10,20,30,10 :header-rows: 1 **CM (Call Control) Packet** .. csv-table:: :file: ./GSM/GSM_packet3_details.csv :widths: 10,20,30,10 :header-rows: 1 **SMS Packet(CP-DATA)** .. csv-table:: :file: ./GSM/GSM_packet4_details.csv :widths: 10,20,30,10 :header-rows: 1 **LAPDm Frame Packet** .. csv-table:: :file: ./GSM/GSM_packet5_details.csv :widths: 10,20,30,10 :header-rows: 1 .. _GSM_step7: .. tab-set:: .. tab-item:: GSM Usecases .. csv-table:: :file: ./GSM/GSM_usecases.csv :widths: 10,20,30 :header-rows: 1 .. _GSM_step8: .. tab-set:: .. tab-item:: GSM Basic Features .. csv-table:: :file: ./GSM/GSM_features.csv :widths: 10,10,30 :header-rows: 1 .. _GSM_step9: .. tab-set:: .. tab-item:: GSM Feature : Digital Voice Transmission **Digital Voice Transmission - Testcases** .. csv-table:: :file: ./GSM/GSM_feature1_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step10: .. tab-set:: .. tab-item:: GSM Feature : SIM-Based Authentication **SIM-Based Authentication - Testcases** .. csv-table:: :file: ./GSM/GSM_feature2_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step11: .. tab-set:: .. tab-item:: GSM Feature : International Roaming **International Roaming - Testcases** .. csv-table:: :file: ./GSM/GSM_feature3_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step12: .. tab-set:: .. tab-item:: GSM Feature : SMS Support **SMS Support - Testcases** .. csv-table:: :file: ./GSM/GSM_feature4_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step13: .. tab-set:: .. tab-item:: GSM Feature : Call and Message Encryption **Call and Message Encryption - Testcases** .. csv-table:: :file: ./GSM/GSM_feature5_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step14: .. tab-set:: .. tab-item:: GSM Feature : Supplementary Services **Supplementary Services - Testcases** .. csv-table:: :file: ./GSM/GSM_feature6_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step15: .. tab-set:: .. tab-item:: GSM Feature : Efficient Spectrum Usage **Efficient Spectrum Usage - Testcases** .. csv-table:: :file: ./GSM/GSM_feature7_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step16: .. tab-set:: .. tab-item:: GSM Feature : Low Power Consumption **Low Power Consumption - Testcases** .. csv-table:: :file: ./GSM/GSM_feature8_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step17: .. tab-set:: .. tab-item:: GSM Feature : Emergency Calling **Emergency Calling - Testcases** .. csv-table:: :file: ./GSM/GSM_feature9_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step18: .. tab-set:: .. tab-item:: GSM Feature : Support for Data Services **Support for Data Services - Testcases** .. csv-table:: :file: ./GSM/GSM_feature10_test_cases.csv :widths: 10,10,30,20 :header-rows: 1 .. _GSM_step19: .. tab-set:: .. tab-item:: Reference links * Reference links