Computer Science GCES OCR
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Cpu Architecture Performance And Embedded Systems Ocr5 主题
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Primary And Secondary Storage Ocr6 主题
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Data Storage And Compression Ocr12 主题
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Units Of Data Storage Ocr
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Processing Binary Data Ocr
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Data Capacity And Calculating Capacity Requirements Ocr
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Converting Between Denary And Binary Ocr
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Binary Addition Ocr
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Converting Between Denary And Hexadecimal Ocr
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Converting Between Binary And Hexadecimal Ocr
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Binary Shifts Ocr
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Representing Characters Ocr
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Representing Images Ocr
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Representing Sound Ocr
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Compression Ocr
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Units Of Data Storage Ocr
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Networks And Topologies Ocr6 主题
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Wired And Wireless Networks Protocols And Layers Ocr6 主题
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Identifying And Preventing Threats To Computer Systems And Networks Ocr2 主题
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Operating Systems And Utility Software Ocr2 主题
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Ethical Legal Cultural And Environmental Impact Ocr2 主题
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Computational Thinking Searching And Sorting Algorithms Ocr3 主题
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Designing Creating And Refining Algorithms Ocr5 主题
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Programming Fundamentals And Data Types Ocr5 主题
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Additional Programming Techniques Ocr7 主题
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Defensive Design And Testing Ocr6 主题
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Boolean Logic Diagrams Ocr2 主题
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Programming Languages And Integrated Development Environments Ides Ocr3 主题
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The Exam Papers Ocr2 主题
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Structuring Your Responses Ocr3 主题
Ip Addressing And Mac Addressing Ocr
Exam code:J277
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Devices on a network send and receive data, a device needs an address to ensure it sends data to the correct place
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There are two types of network address systems:
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IP Address
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MAC Address
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IP Addressing
What is an IP address?
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An IP (Internet Protocol) address is a unique identifier given to devices which communicate over the Internet (WAN)
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IP addresses are dynamic, they can change
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IP addresses make it possible to deliver data to the right device
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A device connecting to a network will be given an IP address, if it moves to a different network then the IP address will change
IPv4
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Internet Protocol version 4 is represented as 4 blocks of denary numbers between 0 and 255, separated by full stops
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Each block is one byte (8 bits), each address is 4 bytes (32 bits)

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IPv4 provides over 4 billion unique addresses (232), however, with over 7 billion people and countless devices per person, a solution was needed
IPv6
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Internet Protocol version 6 is represented as 8 blocks of 4 hexadecimal digits, separated by colons
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Each block is 2 bytes (16 bits), each address is 16 bytes (128 bits)

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IPv6 could provide over one billion unique addresses for every person on the planet (2128)
MAC Addressing
What is a MAC address?
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A MAC (Media Access Control) address is a unique identifier given to devices which communicate over a local area network (LAN)
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MAC addresses are static, they can never change
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MAC addresses make it possible for switches to efficiently forward data to the intended recipient
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Any device that contains a Network Interface Card (NIC) has a MAC address assigned during manufacturing
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A device connecting to a local network already has a MAC address, if it moves to a different network then the MAC address will stay the same

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A MAC address is represented as 12 hexadecimal digits (48 bits), usually grouped in pairs
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The first three pairs are the manufacturer ID number (OUI) and the last three pairs are the serial number of the network interface card (NIC)
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There are enough unique MAC addresses for roughly 281 trillion devices
Worked Example
Computers in a network can be identified using both IP addresses and MAC addresses.
Describe two differences between IP addresses and MAC addresses [2]
Answer
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IP address is dynamic/can change // MAC address is static/cannot change
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IP address is used to communicate on a WAN/Internet // MAC address is used to communicate on a LAN
Responses