Source: https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-1-ip-addresses [Revision notes](https://senecalearning.com/en-gb/revision-notes.md) › [IGCSE](https://senecalearning.com/en-gb/revision-notes/igcse.md) › [Computer Science](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science.md) › [Edexcel IGCSE](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse.md) › IP Addresses # IP Addresses Computer Science: Edexcel IGCSE, topic 5.3.1 ## IP Addresses Just as an address is essential for sending a letter in the post, Internet Protocol (IP) addresses are used to identify where data packets need to be sent to and where they have come from. ### IP addresses ![IP addresses](https://image-v2.cdn.app.senecalearning.com/2018-07/8b8802c8-d4ac-4692-a407-e4ca1a5aa044/IP-Address-Code-Computer-Monitor-Screen-.jpg) - IP addresses are used by routers to determine whether a packet's destination is within the current network or not. - If not, then the router will pass the packet onto the wide area network (WAN), where other routers can use the IP address to figure out where to send the packet. - IP addresses are also used by network applications to specify which device they wish to communicate with. ### Properties of an IP address ![Properties of an IP address](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/OCR%20Gateway/5.1.5/coding%20.jpg) - IP addresses must be unique within the same local area network. - IP addresses do not need to be universally unique. ## Test yourself on IP Addresses - Which piece of networking hardware uses IP addresses? - Routers use an IP address to determine what? [Practise this topic for free](https://app.senecalearning.com/classroom/course/40426d0e-f017-490c-a2b3-c98a77d973bd/section/0697d38b-f2fd-4bb7-a9ee-6fcf744ed381/session) - Previous topic: [5.2.13 Network Forensics](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-13-network-forensics.md) - Next topic: [5.3.2 Types of IP Address](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-2-types-of-ip-address.md) ## Computer Science: Edexcel IGCSE contents ### 1 Problem Solving - 1.1 Algorithms - [1.1.1 Algorithm Thinking](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-1-algorithm-thinking.md) - [1.1.2 Interpreting Algorithms](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-2-interpreting-algorithms.md) - [1.1.3 Expressing Algorithms - Pseudocode](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-3-expressing-algorithms-pseudocode.md) - [1.1.4 Expressing Algorithms - Flow Charts](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-4-expressing-algorithms-flow-charts.md) - [1.1.5 Correcting Algorithms](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-5-correcting-algorithms.md) - [1.1.6 Completing Algorithms](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-6-completing-algorithms.md) - [1.1.7 Search Algorithms](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-7-search-algorithms.md) - [1.1.8 Linear Search](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-8-linear-search.md) - [1.1.9 Binary Search](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-9-binary-search.md) - [1.1.10 Sort Algorithms](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-10-sort-algorithms.md) - [1.1.11 Bubble Sort](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-11-bubble-sort.md) - [1.1.12 Merge Sort](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-1-12-merge-sort.md) - 1.2 Decomposition & Abstraction - [1.2.1 Computational Thinking - Abstraction](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-2-1-computational-thinking-abstraction.md) - [1.2.2 Computational Thinking - Decomposition](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-2-2-computational-thinking-decomposition.md) - [1.2.3 End of Topic Test - Algorithms](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/1-2-3-end-of-topic-test-algorithms.md) ### 2 Programming - 2.1 Develop Code - [2.1.1 Maintainability](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-1-1-maintainability.md) - [2.1.2 Comments](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-1-2-comments.md) - [2.1.3 Exceptions](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-1-3-exceptions.md) - [2.1.4 Syntax Error](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-1-4-syntax-error.md) - [2.1.5 Logic Error](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-1-5-logic-error.md) - [2.1.6 Runtime Error](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-1-6-runtime-error.md) - [2.1.7 Purpose of Testing](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-1-7-purpose-of-testing.md) - [2.1.8 Test Plans](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-1-8-test-plans.md) - 2.2 Constructs - [2.2.1 Selection](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-2-1-selection.md) - [2.2.2 Sequence](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-2-2-sequence.md) - [2.2.3 Iteration](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-2-3-iteration.md) - 2.3 Data Types & Structures - [2.3.1 Variables & Constants](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-3-1-variables-and-constants.md) - [2.3.2 Scope](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-3-2-scope.md) - [2.3.3 Data Types](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-3-3-data-types.md) - [2.3.4 Casting](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-3-4-casting.md) - [2.3.5 Data Structures - Arrays](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-3-5-data-structures-arrays.md) - [2.3.6 Data Structures - 2D Arrays](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-3-6-data-structures-2d-arrays.md) - [2.3.7 Data Structures - Strings](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-3-7-data-structures-strings.md) - [2.3.8 Data Structures - Records](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-3-8-data-structures-records.md) - 2.4 Input / Output - [2.4.1 Input and Output](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-4-1-input-and-output.md) - [2.4.2 Validation and Sanitation](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-4-2-validation-and-sanitation.md) - [2.4.3 Files](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-4-3-files.md) - [2.4.4 File Handling](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-4-4-file-handling.md) - 2.5 Operators - [2.5.1 Arithmetic Operators](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-5-1-arithmetic-operators.md) - [2.5.2 Relational Operators](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-5-2-relational-operators.md) - [2.5.3 Boolean Operators](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-5-3-boolean-operators.md) - 2.6 Subprograms - [2.6.1 Modularity](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-6-1-modularity.md) - [2.6.2 End of Topic Test - Programming](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/2-6-2-end-of-topic-test-programming.md) ### 3 Data - 3.1 Binary - [3.1.1 Number Bases](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-1-1-number-bases.md) - [3.1.2 Negative Binary Numbers](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-1-2-negative-binary-numbers.md) - [3.1.3 Binary Addition](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-1-3-binary-addition.md) - [3.1.4 Binary Shifts](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-1-4-binary-shifts.md) - 3.2 Data Representation - [3.2.1 Representing Text](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-2-1-representing-text.md) - [3.2.2 ASCII](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-2-2-ascii.md) - [3.2.3 Unicode](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-2-3-unicode.md) - [3.2.4 Representing Images](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-2-4-representing-images.md) - [3.2.5 Representing Sound](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-2-5-representing-sound.md) - 3.3 Data Storage & Compression - [3.3.1 Capacity](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-3-1-capacity.md) - [3.3.2 Calculating Capacity Requirements](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-3-2-calculating-capacity-requirements.md) - [3.3.3 Data Compression](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-3-3-data-compression.md) - [3.3.4 Run Length Encoding](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-3-4-run-length-encoding.md) - 3.4 Encryption - [3.4.1 Encryption](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-4-1-encryption.md) - [3.4.2 Caesar Cipher](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-4-2-caesar-cipher.md) - [3.4.3 Ciphers](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-4-3-ciphers.md) - 3.5 Databases - [3.5.1 Databases](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-5-1-databases.md) - [3.5.2 End of Topic Test - Data & Representation](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/3-5-2-end-of-topic-test-data-and-representation.md) ### 4 Computers - 4.1 Machines & Computational Modelling - [4.1.1 Computational Models](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-1-1-computational-models.md) - [4.1.2 Input-Process-Output Model](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-1-2-input-process-output-model.md) - 4.2 Hardware - [4.2.1 Elements of Computer Systems](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-1-elements-of-computer-systems.md) - [4.2.2 Types of Computer Systems](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-2-types-of-computer-systems.md) - [4.2.3 Memory - RAM](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-3-memory-ram.md) - [4.2.4 Memory - ROM](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-4-memory-rom.md) - [4.2.5 Memory - Cache](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-5-memory-cache.md) - [4.2.6 Running Out of Memory](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-6-running-out-of-memory.md) - [4.2.7 Virtual Memory](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-7-virtual-memory.md) - [4.2.8 Magnetic Storage](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-8-magnetic-storage.md) - [4.2.9 Properties of Magnetic Media](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-9-properties-of-magnetic-media.md) - [4.2.10 Examples of Magnetic Storage](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-10-examples-of-magnetic-storage.md) - [4.2.11 Solid State Storage](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-11-solid-state-storage.md) - [4.2.12 Properties of Solid State Media](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-12-properties-of-solid-state-media.md) - [4.2.13 Optical Storage](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-13-optical-storage.md) - [4.2.14 Properties of Optical Storage](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-14-properties-of-optical-storage.md) - [4.2.15 Examples of Optical Storage](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-15-examples-of-optical-storage.md) - [4.2.16 Types of Optical Disk](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-16-types-of-optical-disk.md) - [4.2.17 Von Neumann Architecture](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-17-von-neumann-architecture.md) - [4.2.18 Registers of the Central Processing Unit (CPU)](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-18-registers-of-the-central-processing-unit-cpu.md) - [4.2.19 Fetch-Decode-Execute Cycle](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-19-fetch-decode-execute-cycle.md) - [4.2.20 Factors Affecting CPU Performance](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-20-factors-affecting-cpu-performance.md) - [4.2.21 The Cloud](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-21-the-cloud.md) - [4.2.22 How the Cloud Works](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-22-how-the-cloud-works.md) - [4.2.23 The Cloud - Pros](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-23-the-cloud-pros.md) - [4.2.24 The Cloud - Cons](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-24-the-cloud-cons.md) - [4.2.25 End of Topic Test - Hardware](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-2-25-end-of-topic-test-hardware.md) - 4.3 Logic - [4.3.1 Binary Systems](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-3-1-binary-systems.md) - [4.3.2 Logic Circuits](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-3-2-logic-circuits.md) - [4.3.3 Boolean Logic](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-3-3-boolean-logic.md) - [4.3.4 End of Topic Test - Logic](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-3-4-end-of-topic-test-logic.md) - 4.4 Software - [4.4.1 Operating Systems](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-1-operating-systems.md) - [4.4.2 User Interface Managetment](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-2-user-interface-managetment.md) - [4.4.3 Memory and Process Management](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-3-memory-and-process-management.md) - [4.4.4 File Management](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-4-file-management.md) - [4.4.5 Device Management](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-5-device-management.md) - [4.4.6 User Management](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-6-user-management.md) - [4.4.7 Encryption Software](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-7-encryption-software.md) - [4.4.8 Defragmentation Software](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-8-defragmentation-software.md) - [4.4.9 Data Compression Software](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-9-data-compression-software.md) - [4.4.10 Backup Software](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-4-10-backup-software.md) - 4.5 Programming Languages - [4.5.1 High Level Languages](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-5-1-high-level-languages.md) - [4.5.2 Low Level Languages](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-5-2-low-level-languages.md) - [4.5.3 Translators - Compilers](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-5-3-translators-compilers.md) - [4.5.4 Translators - Interpreters](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-5-4-translators-interpreters.md) - [4.5.5 Translators - Assemblers](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-5-5-translators-assemblers.md) - [4.5.6 End of Topic Test - Translation & Representation](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/4-5-6-end-of-topic-test-translation-and-representation.md) ### 5 Communication & The Internet - 5.1 Networks - [5.1.1 Benefits of Networks](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-1-benefits-of-networks.md) - [5.1.2 Network Performance](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-2-network-performance.md) - [5.1.3 Types of Network](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-3-types-of-network.md) - [5.1.4 Client-Server Model](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-4-client-server-model.md) - [5.1.5 Pros of Client-Server Model](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-5-pros-of-client-server-model.md) - [5.1.6 Cons of Client-Server Model](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-6-cons-of-client-server-model.md) - [5.1.7 Peer-to-Peer Model](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-7-peer-to-peer-model.md) - [5.1.8 Pros of Peer-to-Peer Model](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-8-pros-of-peer-to-peer-model.md) - [5.1.9 Cons of Peer-to-Peer Model](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-9-cons-of-peer-to-peer-model.md) - [5.1.10 Network Hardware](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-10-network-hardware.md) - [5.1.11 Transmission Media](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-11-transmission-media.md) - [5.1.12 WiFi](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-12-wifi.md) - [5.1.13 WiFi Frequency and Channels](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-13-wifi-frequency-and-channels.md) - [5.1.14 WiFi Encryption](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-14-wifi-encryption.md) - [5.1.15 Network Protocols](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-15-network-protocols.md) - [5.1.16 Transmission Protocols](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-16-transmission-protocols.md) - [5.1.17 Web Protocols](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-17-web-protocols.md) - [5.1.18 Email Protocols](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-18-email-protocols.md) - [5.1.19 Layers](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-19-layers.md) - [5.1.20 TCP and OSI Models](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-20-tcp-and-osi-models.md) - [5.1.21 Advantages of Layering](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-21-advantages-of-layering.md) - [5.1.22 Topology - Star](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-22-topology-star.md) - [5.1.23 Topology - Mesh](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-23-topology-mesh.md) - [5.1.24 Topology - Ring](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-24-topology-ring.md) - [5.1.25 Topology - Bus](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-25-topology-bus.md) - [5.1.26 End of Topic Test - Networks](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-1-26-end-of-topic-test-networks.md) - 5.2 Network Security - [5.2.1 User Access Levels](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-1-user-access-levels.md) - [5.2.2 Encryption](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-2-encryption.md) - [5.2.3 Protecting Against Malware](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-3-protecting-against-malware.md) - [5.2.4 Firewalls](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-4-firewalls.md) - [5.2.5 Forms of Attack](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-5-forms-of-attack.md) - [5.2.6 Penetration Testing](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-6-penetration-testing.md) - [5.2.7 Malware](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-7-malware.md) - [5.2.8 How Malware Spreads](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-8-how-malware-spreads.md) - [5.2.9 Social Engineering](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-9-social-engineering.md) - [5.2.10 Protecting Against Social Engineering](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-10-protecting-against-social-engineering.md) - [5.2.11 Phishing](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-11-phishing.md) - [5.2.12 Network Administration](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-12-network-administration.md) - [5.2.13 Network Forensics](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-2-13-network-forensics.md) - 5.3 The Internet & the World Wide Web - [5.3.1 IP Addresses](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-1-ip-addresses.md) - [5.3.2 Types of IP Address](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-2-types-of-ip-address.md) - [5.3.3 MAC Addresses](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-3-mac-addresses.md) - [5.3.4 Packet Switching](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-4-packet-switching.md) - [5.3.5 How Do Packets Get Routed?](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-5-how-do-packets-get-routed.md) - [5.3.6 Did My Data Arrive Safely?](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-6-did-my-data-arrive-safely.md) - [5.3.7 The Internet](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-7-the-internet.md) - [5.3.8 URLs](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-8-urls.md) - [5.3.9 DNS](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-9-dns.md) - [5.3.10 Web Hosting](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-10-web-hosting.md) - [5.3.11 End of Topic Test - Security](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/5-3-11-end-of-topic-test-security.md) ### 6 The Bigger Picture - 6.1 Emerging Trends, Issues & Impact - [6.1.1 E-Waste](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-1-e-waste.md) - [6.1.2 Energy Consumption](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-2-energy-consumption.md) - [6.1.3 Positive Environmental Impact](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-3-positive-environmental-impact.md) - [6.1.4 Ethical Issues - The Digital Divide](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-4-ethical-issues-the-digital-divide.md) - [6.1.5 Ethical Issues - Net Neutrality](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-5-ethical-issues-net-neutrality.md) - [6.1.6 Ethical Issues - Working Conditions](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-6-ethical-issues-working-conditions.md) - [6.1.7 Ethical Issues - Censorship](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-7-ethical-issues-censorship.md) - [6.1.8 Online Activity Tracking](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-8-online-activity-tracking.md) - [6.1.9 The Internet of Things](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-9-the-internet-of-things.md) - [6.1.10 Positive Cultural Impacts](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-10-positive-cultural-impacts.md) - [6.1.11 Negative Cultural Impacts](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-11-negative-cultural-impacts.md) - [6.1.12 Data Protection Act](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-12-data-protection-act.md) - [6.1.13 Computer Misuse Act](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-13-computer-misuse-act.md) - [6.1.14 Copyright Designs and Parents Act](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-14-copyright-designs-and-parents-act.md) - [6.1.15 Creative Commons Licensing](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-15-creative-commons-licensing.md) - [6.1.16 Freedom of Information Act](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-16-freedom-of-information-act.md) - [6.1.17 Open Source Software](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-17-open-source-software.md) - [6.1.18 Proprietary Software](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-18-proprietary-software.md) - [6.1.19 Licensing Issues](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-19-licensing-issues.md) - [6.1.20 End of Topic Test - Software & Issues](https://senecalearning.com/en-gb/revision-notes/igcse/computer-science/edexcel-igcse/6-1-20-end-of-topic-test-software-and-issues.md)