In network and computer systems management there are many "abstractions" and it is useful to have a clear terminology. Definitions / meaning vary depending on context; here is one approximation:
Physical devices: actual device being monitored or managed
Logical devices: abstracting one or more physical devices to expose simpler or extended properties or functionality
Virtual devices: abstracting resources to make it more accessible and manageable; Virtual devices have appearance of physical devices, but actual implementation could be different, sometimes using Logical devices.
logical vs. physical Definition from PC Magazine Encyclopedia "High-level versus low-level. Logical implies a higher view than the physical. Users relate to data logically by data element name; however, the actual fields of data are physically located in sectors on a disk." "Various virtualization methods create a logical "abstraction layer" for dealing with the physical hardware. For example, virtual machines enable multiple operating systems to run in the computer, each accessing the hardware via a logic layer rather than direct physical contact." logical vs. physical topology Definition from PC Magazine Encyclopedia "A logical topology is how devices appear connected to the user. A physical topology is how they are actually interconnected with wires and cables."
Re: [vnrg] Logical vs. virtual @ IETF "a virtual resource appears to a user of that resource
as if he is the (exclusive) owner of that resource.
A user's access is always carried out on the real resource.
Thus, a virtual resource simplifies the handling of
a scarce real resource, while hiding the shortage. Virtual
memory is a typical example here - a process can use
a larger virtual memory than there is physically real
linux kernel - Difference between physical/logical/virtual memory address - Stack Overflow "Virtual address: The address you use in your programs, the address that your CPU use to fetch data, is not real and gets translated via MMU to some physical address; everyone has one and its size depends on your system(Linux running 32-bit has 4GB address space) Physical address: The address you'll never reach if you're running on top of an OS; it's where your data, regardless of its virtual address, resides in RAM; this will change if your data is sent back and forth to the harddisk to accommodate more space for other processes."
"logical address" means that the address the program sees is different from the physical address of the data being stored in RAM. If you have virtual memory, there may be no physical address at all, as the data stored could be swapped out to disk."