During the last years several operators have expressed concerns about the continued growth of the BGP routing tables in the default-free zone. Proposed solutions for this issue are centered around the idea of separating the network node’s identifier from its topological location. Among the existing proposals, the Locator/ID Separation Protocol (LISP) is the one with the biggest momentum. In LISP, a mapping system is required to provide bindings between locators and identifiers. In this paper we present a new mapping system: LISP-TREE. It is based on DNS and has a similar hierarchical topology: blocks of identifiers (EIDs) are assigned to the levels of the hierarchy by following the current IP address allocation policy. It can work with the existing DNS implementations, providing the benefit of 20 years of operational experience. In addition, we present measurement-driven simulations of mapping systems’ performance, assuming deployment of LISP in the current Internet.