PhysicalAddress

PhysicalAddress is a data type used in computing to represent the hardware address of a network interface, commonly referred to as a MAC address. It is typically implemented as an ordered sequence of bytes, with the length varying by encoding. The most common form uses 6 bytes (MAC-48), while other forms such as EUI-64 use 8 bytes; some contexts may allow different lengths or representations.

In many programming environments, a PhysicalAddress type encapsulates this value, storing the address as a byte array and providing operations to access the bytes, determine the length, compare addresses, and convert to and from a human-readable form. A typical textual representation renders the bytes as hexadecimal values separated by colons or hyphens, for example 00:1A:2B:3C:4D:5E.

Usage of PhysicalAddress includes identifying a specific network interface for management and configuration tasks, filtering network traffic, or binding operations to a particular adapter. Interfaces in various APIs expose their hardware address through a PhysicalAddress-like construct, enabling programs to enumerate devices and retrieve their addresses.

Limitations and caveats: the physical address is assigned by the device manufacturer and may be subject to change in some environments, such as through spoofing, virtualization, or software-defined networking. In virtual machines or containers, the address presented to the guest may differ from the physical hardware. Access to a device’s MAC address may be restricted by privacy or security policies, and in some platforms the address may be unavailable.

See also: MAC address, EUI-64, network interface, IP address.