Purchasing power parity (PPP) is an economic theory that states that the exchange rate between two currencies is equal to the ratio of the currencies' respective purchasing power.
MAC Address Generation. Each virtual network adapter in a virtual machine is assigned its own unique MAC address. Each network adapter manufacturer is assigned a unique three-byte prefix called an Organizationally Unique Identifier (OUI), which it can use to generate unique MAC addresses.
It is the 12 hexadecimal digit combination identifying the manufacturer and id of your NIC. the first 6 digits is the OUI(Organizationally unique Identifier), this identifies the company that made the NIC. the last 6 digits is the USI(Unique station identifier) this identifies your NIC.