IP address
An IP address serves two principal functions. It identifies the host, or more specifically its network interface, and it provides the location of the host in the network, and thus the capability of establishing a path to that host. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."
The header of each IP packet contains the IP address of the sending host, and that of the destination host.
Locator/Identifier Separation Protocol
Locator/ID Separation Protocol (LISP) () is a "map-and-encapsulate" protocol which is developed by the Internet Engineering Task Force LISP Working Group. The basic idea behind the separation is that the Internet architecture combines two functions, routing locators (where a client is attached to the network) and identifiers (who the client is) in one number space: the IP address. LISP supports the separation of the IPv4 and IPv6 address space following a network-based map-and-encapsulate scheme (). In LISP, both identifiers and locators can be IP addresses or arbitrary elements like a set of GPS coordinates or a MAC address.