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.
1 The HA-SKU Unique Device Identifier (UDI) provides the capability of the maximum number of APs supported on that hardware. For instance, a 5508 HA- SKU controller provides support for 500 APs.  The N+1 Secondary HA-SKU cannot be configured in combination with AP SSO.