0478 Computer Science
Chpater 1 Number System
1.1 Number systems
1.2 Text, sound and images
1.3 Data storage and compression
Chapter 2 Data transmission
2.1 Types and methods of data transmission
2.2 Methods of error detection
2.3 Encryption
Chapter 3 Hardware
3.1 Computer architecture
3.2 Input and output devices
3.3 Data storage
3.4 Network hardware
Chapter 4 Software
4.1 Types of software and interrupts
4.2 Types of programming language, translators and integrated development environments (IDEs)
Chapter 5 The internet and its uses
5.1 The internet and the World Wide Web (WWW)
5.2 Digital currency
5.3 Cyber security
Chapter 6 Automated and emerging technologies
6.1 Automated systems
6.2 Robotics
6.3 Artificial intelligence (AI)
Chapter 7 Algorithm design and problem solving
7.1 The program development life cycle
7.2 Computer systems, sub-systems anddecomposition
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Chapter 8 Programming
8.1 Programming concepts
8.2 Arrays
Mr. Theo
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3.4 Network hardware
## Network interface card (NIC) this is a component in a device that enables it to connect to a network ## Router a device that forwards packets to their correct destinations in a network - The router examining the packet looks for the packet header, looking for the IP address of destination - The packet being sent toward its correct destination by the fastest route // decides which route it takes - Router is shown connecting devices/networks - Router is shown assigning an IP address to a device  ## Firewall // proxy-server this can be hardware or software based and filters traffic coming into and out of a network #### Media Access Control (MAC) address this address is assigned by the manufacturer and is used to uniquely identify the device - Media access control - Unique address given to each device - It is assigned by the manufacturer - It can be used to identify a device - Does not (usually) change // static ##### Structure: - Uses hexadecimal values - Normally 48/64 bits in length (accept any other reasonable value) - First half is manufacturer number/code/ID - Second half is serial number #### IP address this address is assigned by the network and used to identify a device on a network - Gives each device on a network an identifier // IP address used to locate a device on a network - Each address is unique within the network - Allows a device/gateway/node to send data to the correct destination / a specific device/gateway/node | Static IP address | Dynamic IP address | | ------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------- | | A fixed, unchanging network identifier assigned to a device, | It can change each time the device is connected to the network | | Static IP addresses are useful when websites need to remember a device for a long time. Eg) VPNs whitelisting | Dynamic IP address is relatively more secure, hence used where data privacy is important | | Faster upload/download speeds | Maintaining cost of dynamic IP address is lesser | ##### IPv4: - Four groups of denary or Hexadecimal integers separated by dots - Numbers between 0 and 255 / 0 and FF - Each stored in 1 byte / 8 bits // the whole is stored in 32 bits / 4 bytes - Eg: 123.234.5.35 ##### IPv6: - 128-bits/16bytes address format - Eight groups of hexadecimal digits separated by colons - Each stored in 2 bytes/16bits - Eg: 3ffe:1900:4545:3a7b:200a:f8ff:fe2i:67cf #### IPv6 Compression: Step1: Remove Leading Zeros ``` 67A1:0045:0010:0052:0001:0012:8000 => 67A1:45:10:52:1:12:8000 ``` Step 2:Remove Inline Zeros ``` 67A1:0000:0000:0000:0001:0012:8000 => 67A1::1:12:8000 ``` **This can be used anywhere in an address, start, middle or end However this::can only be used once in one address ``` eg: 8055:F2F2:0000:0000:FFF1:0000:0000:DD04 => 8055:F2F2::FFF1:0000:0000:DD04 OR => 8055:F2F2:0000:0000:FFF1::DD04 ``` | | iipv4 | ipv6 | | ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------- | | Similarity | They can both be used to identify a device (on a network)<br>They can both be static / dynamic<br>They are both unique (to a device on a network)<br>They can both be assigned by a router<br>They can both be public/private | | | Differences | usually written as denary | usually written as hexadecimal | | | is separated using dots | is separated using colons | | | is 32-bit | is 128-bit | | | is 4 groups of digits | is 8 groups of digits | | | digits are between 0 and 255 | digits are between 0000 and FFFF | | | all 0s are displayed | can use double colons to replace repeated groups of 0000 | | | has fewer available unique addresses | has more available unique addresses | ## Domain name server // DNS the system that stores a database of uniform resource locators (URLs) and their corresponding IP addresses ## Web browser the software that sends a request to the IP address to obtain the web page data
Theo
2025年9月10日 07:26
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