The Locator/ID Separation Protocol (LISP) as per RFC 6830 is a new routing architecture that splits an IP address into two entities: The routing locator (RLOC) and the endpoint identifier (EID). The goal is to achieve a highly scalable routing architecture with integrated routing, tunneling and overlay protocols.
Conventional routing protocols such as RIP, OSPF or BGP work according to the "push principle" and proactively distribute their best routes to their neighbors. This architecture is of limited scalability, as the ever larger BGP tables and routing tables increasingly become a challenge.
LISP works according to the "pull principle" and works much like the Domain Name System (DNS). LISP routers register their networks, referred to as endpoint identifiers (EIDs), at a central instance called a map server or map resolver. Along with the EID, they also register their global (WAN) address, called the routing locator (RLOC). This keeps the information about the location (locator) separate from the identity (ID).
If a router wants to transfer data to a remote LISP network, first the LISP map resolver is queried for the mappings between the requested EID prefix and the routing locator. In the next step, a data tunnel is established between the two LISP routers.
LISP currently does not provide encryption of the data tunnel and, when used in insecure networks such as the Internet, it is typically combined with VPN. Application scenarios for LISP are multi-VPNs.
LCOS as of LCOS version 10.20 supports the following roles:
- Ingress tunnel router (ITR)
- Egress tunnel router (ETR)
The role of the map server/map resolver is currently not supported.
