LISP stands for not just the programming language, but for the Locator/ID Separation Protocol as well, which is a soon-to-be-finalized IETF standard. LISP can be used to improve network layer mobility, by assigning a static Endpoint IDentifier (EID) to hosts, which are mapped to a Routing LOCator (RLOC) identifying the network point of attachment. Both EIDs and RLOCs are IP addresses. Transport layer connections use EIDs, while packets are traveling in dynamic point-to-point tunnels using RLOCs for encapsulation between hosts, thus avoiding path stretch.

The LISP Mobile Node specification enables maintaining the same IP address regardless of network attachment point, and address family combination. For example, a device can use an IPv4 address on an IPv4-only, IPv6-only, or dual stack network. Since a roaming event does not change the IP address used by transport layer, ongoing connections (such as a SIP call) are maintained. Additionally, nodes with several available interfaces can define active-backup, or active-active load balanced incoming traffic policies.

The LISPmob Project is an implementation of the above specification for Linux, consisting of two kernel modules and a user space daemon.