Locator/ID Separation Protocol
Locator/ID Separation Protocol WG
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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. 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.
A number of approaches are being looked at in parallel in other
contexts. The IRTF RRG examined several proposals, some of which were
published as IRTF-track Experimental RFCs.
The LISP WG has completed the first set of Experimental RFCs
describing the Locator/ID Separation Protocol. LISP requires no
changes to end-systems or to routers that do not directly participate
in the LISP deployment. LISP aims for an incrementally deployable
The LISP WG is chartered to continue work on the LISP base protocol,
the ongoing work, and any items which directly impact LISP protocol
structures and which are related to using LISP for improving Internet routing
scalability. Specifically, the group will work on:
- Architecture description: This document will describe the
architecture of the entire LISP system, making it easier to read the
rest of the LISP specifications and providing a basis for discussion
about the details of the LISP protocols. The document will include
a description of the cache management and ETR synchronization
essential characteristics needed to ensure the correct operation
of the protocol.
- Deployment models: This document will describe what kind of
deployments can be expected for LISP, and give operational advice on
how they can be set up.
- A description of the impacts of LISP: This document will describe
the problems that LISP is intended to address and the impacts that
employing LISP has. While the work on LISP was initiated by Internet
routing scaling concerns, there has also been an interest on
improved solutions to a number of different problems, such as
traffic engineering. This document should describe problem areas
(such as scaling or traffic engineer) where LISP is expected to have
a positive effect, as well as any tradeoffs that are caused by
- LISP security threats and solutions: This document will describe the
security analysis of the LISP system, what issues it needs to
protect against, and a solution that helps defend against those
issues. The replay attack problem discussed on the mailing list
should be included in this work.
- Allocation of Endpoint IDentifier (EID) space: This document
requests address space to be used for the LISP experiment as
- Alternate mapping system designs: Develop alternative mapping
designs to be tested.
- Data models for management of LISP.
The first three items (architecture, deployment models, impacts) need
to be completed first before other items can be submitted as RFCs. The
three first documents also need to complement each other, by
describing how the architecture supports a solution for a particular
problem area and how the solution can be deployed to help with that
In addition, if work chartered in some other IETF WG requires changes
in the LISP base protocol or any items which directly impact LISP
protocol structures, then the LISP WG is chartered to work on such
It is expected that the results of specifying, implementing, and testing
LISP will be fed to the general efforts at the IETF and IRTF to
understand which type of a solution is optimal. The LISP WG is not
chartered to develop a standard solution for solving the routing
scalability problem at this time. The specifications developed by the WG
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.