5.5. Using Virtualization and Segmentation with LISP

5.5. Using Virtualization and Segmentation with LISP

When multiple organizations inside of a LISP site are using private addresses [RFC1918] as EID-Prefixes, their address spaces MUST remain segregated due to possible address duplication. An Instance ID in the address encoding can aid in making the entire AFI-based address unique. See IANA Considerations (Section 14.2) for details on possible address encodings.

An Instance ID can be carried in a LISP-encapsulated packet. An ITR that prepends a LISP header will copy a 24-bit value used by the LISP router to uniquely identify the address space. The value is copied to the 'Instance ID' field of the LISP header, and the I-bit is set to 1.

When an ETR decapsulates a packet, the Instance ID from the LISP header is used as a table identifier to locate the forwarding table to use for the inner destination EID lookup.

For example, an 802.1Q VLAN tag or VPN identifier could be used as a 24-bit Instance ID.