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2.7 Hexadecimal conversion and MAC
Conversion
In computer science, base conversion is the process of converting a value from one base representation to another. Common bases include binary (base-2), decimal (base-10), octal (base-8), and hexadecimal (base-16).
The following are examples of common base conversions:
- Binary to Decimal: Convert binary numbers to decimal numbers, for example, binary number 1101 is converted to decimal number 13.
- Decimal to Binary: Convert a decimal number to a binary number, for example, the decimal number 27 is converted to the binary number 11011.
- Decimal to Hexadecimal: Convert a decimal number to a hexadecimal number, for example, convert the decimal number 255 to the hexadecimal number FF.
- Hexadecimal to Decimal: Convert a hexadecimal number to a decimal number, for example, convert the hexadecimal number 1A to the decimal number 26.
Base conversion is widely used in computers, especially in the process of data representation and transmission in networks and storage.
MAC address
A MAC (Media Access Control) address, also known as a physical address, is a unique identifier for a network device (such as a network card). Every network device has a unique MAC address, consisting of 12 hexadecimal numbers, usually separated by colons or dashes.
The MAC address is composed of two parts: the first 6 hexadecimal digits represent the manufacturer's identification (that is, the vendor's unique identifier, OUI), and the latter 6 hexadecimal digits represent the device serial number.
For example, a device's MAC address might be: 00:1A:2B:3C:4D:5E.
MAC addresses are used in local area networks to uniquely identify devices, and in data link layers such as Ethernet for communication between devices. It is used in packets to determine the recipient of the packet.
The relationship between MAC address and IP address
MAC address and IP address are two different network identifiers. MAC addresses are used for communication between devices at the data link layer, while IP addresses are used for communication between devices at the network layer.
In the local area network, when data is sent from the source device to the target device, the data first finds the target device through the IP address of the target device, and then finds the network card of the target device through the MAC address of the target device, so as to realize the data transmission.
ARP (Address Resolution Protocol) is used to resolve an IP address into a corresponding MAC address. When a device needs to communicate with another device, it first sends an ARP request broadcast asking for the MAC address of the device with a specific IP address. After receiving the ARP request, the target device replies its own MAC address to the source device, thereby establishing the mapping relationship between the IP address and the MAC address.
Summarize
Base conversion is the process of converting a value from one base to another base. Common bases include binary, decimal, octal, and hexadecimal. A MAC address is a unique identifier for a network device and consists of 12 hexadecimal digits. The MAC address is used for communication between devices in the data link layer, and the IP address is resolved to the corresponding MAC address through ARP. Understanding the concept and application of base conversion and MAC address is helpful to understand the data representation and communication process in computer network.