Locator/ID Separation: Study on the cost of Mappings Caching and Mappings Lookups

Very recent activities in the IETF and in the Routing Research Group (RRG) of the IRTG focus on defining a new Internet architecture, in order to solve scalability issues related to interdomain routing. The approach that is being explored is based on the separation of the end-systems ’ addressing space (the identifiers) and the routing locators ’ space. This separation is meant to alleviate the routing burden of the Default Free Zone, but it implies the need of distributing and storing mappings between identifiers and locators on caches placed on routers. In this technical report we evaluate the cost of maintaining these caches and requesting these mappings when the distribution mechanism is based on a pull model. Taking as a reference the LISP protocol, we base our evaluation on real Netflow traces collected on the border router of our campus network. We thoroughly analyze the impact of the locator/ID separation, and related cost, showing that there is a trade-off between the dynamism of the mapping distribution protocol, the demand in terms of bandwidth, and the size of the caches.