RFC 2103 (rfc2103) - Page 3 of 17
Mobility Support for Nimrod : Challenges and Solution Approaches
Alternative Format: Original Text Document
RFC 2103 Nimrod Mobility Support February 1997 Thus, providing a solution to mobility in the context of Nimrod may be perceived as one of maintaining a dynamic association between the endpoints and the locators. Extending this viewpoint further, one can think of mobility-capable Nimrod as essentially consisting of two "modules": the Nimrod routing module and the dynamic association module (DAM). The DAM is an abstraction, embodying the functionality pertinent to maintaining the dynamic association. This is a valuable paradigm because it facilitates the comparison of various mobility schemes from a common viewpoint. Our discussion will be structured based on the DAM abstraction and will be in two parts, the themes of which are : o What constitutes mobility for the DAM and Nimrod? Is the realization of mobility as a mobility "module" that interacts with Nimrod viable? What then are the interactions between Nimrod and such a module? These points will be discussed in section 3. o What are some of the approaches one can take in engineering the DAM functionality? We classify some approaches and compare them in section 4. A word of caution: the DAM should not be thought of as something equivalent to the current day Domain Name Service (DNS) - the DAM is a more general concept than that. For instance, consider a mobility solution for Nimrod similar to the scheme described in [Sim94]. Very roughly, this approach is as follows: Every endpoint is associated with a "home" locator. If the endpoint moves, it tells a "home representative" about its new locator. Packets destined for the endpoint sent to the old locator are picked up by the home representative and sent to the new locator. In this scheme, the DAM embodies the functionalities implemented by all of the home representatives in regard to tracking the mobile hosts. The point is that the association maintenance, while required in some form or other, may not be an explicitly distinct part, but implicit in the way mobility is handled. Thus, the DAM is merely an abstraction useful to our discussion and should not be construed as dictating a design. In summary, we view the Nimrod architecture as carrying a functional "stub" for mobility, the details of the stub being deferred for later. The stub will be elaborated when a solution that meets the requirements of Nimrod becomes available (for instance from the IETF Mobile-IP research). We do not, however, preclude the modification of any such solutions to meet the Nimrod requirements or preclude the development of an independent solution within Nimrod. Ramanathan Informational
