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Locator/ID Separation Protocol (lisp) (WG)

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Meeting Slides


No Request For Comments

Charter (as of 2011-10-11)

The IAB's October 2006 Routing and Addressing Workshop (RFC 4984)
rekindled interest in scalable routing and addressing architectures for
the Internet. Among the many issues driving this renewed interest are
concerns about the scalability of the routing system and the impending
exhaustion of the IPv4 address space. Since the IAB workshop, several
proposals have emerged which attempt to address the concerns expressed
there and elsewhere. In general, these proposals are based on the
"locator/identifier separation".

The basic idea behind the separation is that the Internet architecture
combines two functions, routing locators, (where you are attached to the
network) and identifiers (who you are) in one number space: The IP
address. Proponents of the separation architecture postulate that
splitting these functions apart will yield several advantages, including
improved scalability for the routing system. The separation aims to
decouple locators and identifiers, thus allowing for efficient
aggregation of the routing locator space and providing persistent
identifiers in the identifier space.

LISP supports the separation of the IPv4 and IPv6 address space
following a network-based map-and-encapsulate scheme (RFC 1955). In
LISP, both identifiers and locators are IP addresses. In LISP,
identifiers are composed of two parts: a "global" portion that uniquely
identifies a particular site and a "local" portion that identifies an
interface within a site. The "local" portion may be subdivided to
identify a particular network within the site. For a given identifier,
LISP maps the "global" portion of the identifier into a set of locators
that can be used by de-capsulation devices to reach the identified
interface; as a consequence a host would typically change identifiers
when it moves from one site to another or whenever it moves from one
subnet to another within an site. Typically, the same IP address will
not be used as an identifier
and locator in LISP.

LISP requires no changes to end-systems or to most routers. LISP aims
for an incrementally deployable protocol.

A number of approaches are being looked at in parallel in the IRTF and
IETF. At this time, these proposals are at an early stage. All proposals
(including LISP) have potentially harmful side-effects to Internet
traffic carried by the involved routers, have parts where deployment
incentives may be lacking, and are NOT RECOMMENDED for deployment beyond
experimental situations at this stage. Many of the proposals have
components (such as the identifier to locator mapping system) where it
is not yet known what kind of design alternative is the best one among

However, despite these issues it would be valuable to write concrete
protocol specifications and develop implementations that can be used to
understand the characteristics of these designs. The LISP WG is
chartered to work on the LISP base protocol
(draft-farinacci-lisp-12.txt), the LISP+ALT mapping system
(draft-fuller-lisp-alt-05.txt), LISP Interworking
(draft-lewis-lisp-interworking-02.txt), LISP Map Server
(draft-fuller-lisp-ms-00.txt), and LISP multicast
(draft-farinacci-lisp-multicast-01.txt) for these purposes, with the
given drafts as a starting point. The working group will encourage and
support interoperable LISP implementations as well as defining
requirements for alternate mapping systems. The Working Group will also
develop security profiles for the ALT and/or other mapping systems.

It is expected that the results of specifying, implementing, and testing
LISP will be fed to the general efforts at the IETF and IRTF (e.g., the
Routing Research Group) that attempts to understand which type of a
solution is optimal. The LISP WG is NOT chartered to develop the final
or standard solution for solving the routing scalability problem. Its
specifications are Experimental and labeled with accurate disclaimers
about their limitations and not fully understood implications for
Internet traffic. In addition, as these issues are understood, the
working group will analyze and document the implications of LISP on
Internet traffic, applications, routers, and security. This analysis
will explain what role LISP can play in scalable routing. The analysis
should also look at scalability and levels of state required for
encapsulation, decapsulation, liveness, and so on
(draft-meyer-loc-id-implications) as well as the manageability and
operability of LISP.

Goals and Milestones:

Mar 2010  Submit base LISP specification to the IESG as Experimental
Mar 2010  Submit base ALT specification to the IESG as Experimental
Mar 2010  Submit the LISP Interworking specification to the IESG as Experimental
Jun 2010  Submit the LISP Map Server specification to the IESG as Experimental
Jun 2010  Submit Recommendations for Securing the LISP Mapping System to the IESG as Experimental
Jul 2010  Submit LISP for Multicast Environments to the IESG as Experimental
Dec 2010  Submit a preliminary analysis as Informational
Dec 2010  Re-charter or close.