What is Logical Addressing?

Logical addressing is a method of addressing memory or network devices that allows the operating system or network layer to decouple the addresses that are seen by application programs from the physical addresses of the underlying hardware. This decoupling provides a number of benefits, including:

Flexibility: Logical addresses can be reassigned or remapped without affecting the application programs that are using them. This can make it calmer to manage memory and networks, and to support features such as virtual memory and dynamic routing.

Security: Logical addresses can be used to protect memory and network resources from unauthorized access. For example, the operating system can use logical addresses to isolate the memory of different processes from each other.

Abstraction: Logical addresses hide the details of the underlying hardware from application programs. This makes it easier to develop and port programs to different platforms.

In computer memory, logical addresses are also known as virtual addresses. Virtual addresses are translated into physical speeches by the memory management unit (MMU). The MMU is a hardware component that sits between the CPU and the memory bus. It maintains a page table, which is a data structure that maps virtual addresses to physical addresses.

In networking, logical addresses are also known as IP addresses. IP addresses are used to classify devices on a network and to route packets between them. IP addresses are assigned by network administrators or by DHCP servers.

Here are some examples of logical addressing:

The operating system uses logical addresses to manage the memory of different processes.

The web browser uses logical addresses to access web pages and other capitals on the Internet.

A router uses logical addresses to route packets between different networks.

Logical addressing is an essential part of modern computing and networking. It provides a number of benefits, including flexibility, security, and abstraction.

What is a logical address in a layer?

A logical address in a layer is an address that is used by a protocol in that layer to identify devices or resources. Logical addresses are typically independent of the physical addresses used in the lower layers of the protocol stack.

For example, in the OSI model, the network layer uses logical addresses to identify devices on a network. These logical addresses are typically IP addresses. The data link coating uses physical addresses to identify devices on a local network. These physical addresses are typically MAC addresses.

The network layer protocols are responsible for translating logical addresses into physical addresses. This process is called address resolution.

Here are some examples of logical addresses in different layers of the OSI model:

Network layer: IP address

Transport layer: TCP port number, UDP port number

Application layer: HTTP URL, FTP hostname

Logical addresses are used for a variety of purposes, including:

Routing: Logical addresses are used to route packets between devices on a network.

Addressing: Logical addresses are used to identify devices and resources on a network.

Security: Logical addresses can be used to protect devices and resources from unauthorized access.

Isolation: Logical addresses can be used to isolate different devices and resources from each other.

Logical addressing is an essential part of modern networking. It allows for a variety of benefits, including flexibility, security, and scalability.

What is logical addressing and physical addressing?

Logical addressing is a method of addressing memory or network devices that allows the operating system or network layer to decouple the addresses that are seen by application programs from the physical addresses of the underlying hardware.

Physical addressing is the direct mapping of logical addresses to physical addresses. This means that the address that is used by the CPU to access a memory location or network device is the same as the physical address of that location or device.

Logical addressing is more flexible and efficient than physical addressing. It allows the operating system to manage memory and networks more efficiently, and to support features such as virtual memory and dynamic routing. It also allows application programs to be developed and ported to different platforms more easily.

Here is an example of the difference between logical addressing and physical addressing:

A computer has a physical memory address space of 4 GB.

The operating system uses logical addressing to manage the memory of the computer.

The operating system creates a logical address space of 8 GB for each application program.

The operating system uses a page table to chart the logical addresses of each application program to physical memory addresses.

When an application program tries to access a memory location, the operating system uses the page table to translate the logical address to a physical memory address. The operating system then accesses the memory location at the physical memory address.

The application program is not aware of the physical memory addresses. It only sees the logical addresses. This allows the operating system to move the application program's memory anywhere in physical memory without affecting the application program itself.

Logical addressing is used in both computer memory and networking. In computer memory, logical addresses are also known as virtual addresses. In networking, logical addresses are also known as IP addresses.

Here are some of the benefits of logical addressing:

Flexibility: Logical addresses can be reassigned or remapped without affecting the application programs that are using them. This can make it calmer to manage memory and networks, and to support features such as virtual memory and dynamic routing.

Security: Logical addresses can be used to protect memory and network resources from unauthorized access. For example, the operating system can use logical addresses to isolate the memory of different processes from each other.

Abstraction: Logical addresses hide the details of the underlying hardware from application programs. This makes it easier to develop and port programs to different platforms.

Logical addressing is an essential part of modern computing and networking. It provides a number of benefits, including flexibility, security, and abstraction.