LISP DDT node, installed at CSUC for five years with the collaboration of the Universitat Politècnica de Catalunya (UPC) and Cisco technology, has made possible to test this new protocol first-hand and turn it into a mature technology that has had a significant impact on the field of private VPNs and mobility.
LISP is a network architecture that builds new semantics for IP addresses, along with several number of protocols. It is based on the separation of current IP addresses into two namespaces: the Endpoint Identifiers (EID), which are relatively static and are used for end-to -end communications; and the Routing Locators (RLOC), which are more dynamic and are used for routing and forwarding on the internet. in an effort to make it more understandable, the analogy saying that LISP separates the “Where?” (RLOC) from the “Who?” (EID) can help. With LISP, nothing must be changed on the hosts, changes are passed to the network and encapsulated.
LISP DDT is a hierarchical and distributed database that provides a mapping between EID and RLOC in a very similar way to how DNS servers work. LISP DDT provides delegation information to map-resolvers, which use the information for EID-RLOC mappings. A map-resolver which needs to locate a given mapping will fllow a path through the tree-structured database, contacting, one after another, the DDT nodes along that path until it reaches the leaf DDT node authoritative for the mapping it is seeking.
Root DDT nodes, as the one installed so far at CATNIX, are on the top of the hierarchy, as are DNS root servers too.