The continuous growth of the Internet presents several challenges. Among the most fundamental challenges is ensuring that the routing and addressing system continues functioning efficiently even as the number of connected devices increases.

During early network research and development work, a fundamental observation was that the single IP address, including identity and location, leads to suboptimal route scaling and hinders multihoming and device mobility.

Locator ID Separation Protocol (LISP) provides improved routing scalability and facilitates flexible address assignment for multi-homing provider independence, mobility, and virtualization.

LISP offers an alternative to traditional Internet architecture by introducing two separate IP addresses: one to indicate routing locators (RLOCs) for routing traffic through the global Internet and a second for endpoint identifiers (EIDs) to identify network sessions between devices.

Locator ID Separation Protocol (LISP) is a network architecture and protocol that implements the use of two namespaces instead of a single IP address:

• Endpoint identifiers (EIDs)—assigned to end hosts.
• Routing locators (RLOCs) are assigned to routers) that comprise devices

Splitting EID and RLOC functions yields several advantages, including improved routing system scalability, multihoming efficiency, and ingress traffic engineering.

LISP functionality requires LISP-specific configuration of one or more LISP-related devices, such as the LISP egress tunnel router (ETR), ingress tunnel router (ITR), proxy ETR (PETR), proxy ITR (PITR), map resolver (MR), map server (MS), and LISP alternative logical topology (ALT) device.