Locator/ID Separation Protocol (LISP): Shared Extension Message & IANA Registry for Packet Type Allocations

The Locator/ID Separation Protocol (LISP) base specification, , defines a set of primitives that are identified with a packet type code. Several extensions have been proposed to add more LISP functionalities. It is expected that additional LISP extensions will be proposed in the future. The "LISP Packet Types" IANA registry (see ) is used to ease the tracking of LISP message types. Because of the limited type space and the need to conduct experiments to assess new LISP extensions, this document specifies a shared LISP extension message type and describes a procedure for registering LISP shared extension sub-types (see ). Concretely, one single LISP message type code is dedicated to future LISP extensions; sub-types are used to uniquely identify a given LISP extension making use of the shared LISP extension message type. These identifiers are selected by the author(s) of the corresponding LISP specification that introduces a new LISP extension message type.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

depicts the common format of the LISP shared extension message. The type field MUST be set to 15 (see ).

The "Sub-type" field conveys a unique identifier that MUST be registered with IANA (see ). The exact structure of the 'extension-specific' portion of the message is specified in the corresponding specification document.

This document does not introduce any additional security issues other than those discussed in .

IANA has created a protocol registry for LISP Packet Types, numbered 0-15. Values can be assigned via Standards Action . Documents that request for a new LISP packet type may indicate a preferred value in the corresponding IANA sections. IANA is requested to replace the reference to RFC8113 with the RFC number to be assigned to this document. Also, IANA is requested to update the table as follows:

IANA has created the "LISP Shared Extension Message Type Sub-types" registry. IANA is requested to update that registry by replacing the reference to RFC8113 with the RFC number to be assigned to this document. The values in the range 0-1023 are assigned via Standards Action. This range is provisioned to anticipate, in particular, the exhaustion of the LISP Packet types. The values in the range 1024-4095 are assigned on a First Come, First Served (FCFS) basis. The registration procedure should provide IANA with the desired codepoint and a point of contact; providing a short description (together with an acronym, if relevant) of the foreseen usage of the extension message is also encouraged.

The following changes were made from RFC 8113: Change the status from Experimental to Standard track. Indicate explicitly that the shared extension is used for two purposes: extend the type space and conduct experiments to assess new LISP extensions. Delete pointers to some examples illustrating how the shared extension message is used to extend the LISP protocol. Request IANA to update the "IANA LISP Packet Types" and "LISP Shared Extension Message Type Sub-types" registries to point to this document instead of RFC8113.

This work is partly funded by ANR LISP-Lab project #ANR-13-INFR-009-X. Many thanks to Luigi Iannone, Dino Farinacci, and Alvaro Retana for the review. Thanks to Geoff Huston, Brian Carpenter, Barry Leiba, and Suresh Krishnan for the review.