Darrel Lewis

LISP: a southbound SDN protocol?

The Locator/ID Separation Protocol (LISP) splits current IP addresses overlapping semantics of identity and location into two separate names-paces. Since its inception the protocol has gained considerable attention from both industry and academia, motivating several new use cases to be proposed. Despite its inherent control-data decoupling and the abstraction and flexibility it introduces into the network, little has been said about the role of LISP on the SDN paradigm. In this article we try to fill that gap and analyze if LISP can be used for SDN. The article presents a systematic analysis of the relevant SDN requirements and how such requirements can be fulfilled by the LISP architecture and components. This results in a set of benefits (e.g. incremental deployment, scalability, flexibility, interoperability, and inter-domain support) and drawbacks (e.g. extra headers and some initial delay) of using LISP for SDN. In order to validate the analysis, we have built and tested a prototype using the LISPmob open-source implementation.

An analytical model for Loc/ID mappings caches

Concerns regarding the scalability of the interdomain routing have encouraged researchers to start elaborating a more robust Internet architecture. While consensus on the exact form of the solution is yet to be found, the need for a semantic decoupling of a nodes location and identity is generally accepted as a promising way forward. However, this typically requires the use of caches that store temporal bindings between the two namespaces, to avoid hampering router packet forwarding speeds. In this article, we propose a methodology for an analytical analysis of cache performance that relies on the working-set theory. We first identify the conditions that network traffic must comply with for the theory to be applicable and then develop a model that predicts average cache miss rates relying on easily measurable traffic parameters. We validate the result by emulation, using real packet traces collected at the egress points of a campus and an academic network. To prove its versatility, we extend the model to consider cache polluting user traffic and observe that simple, low intensity attacks drastically reduce performance, whereby manufacturers should either overprovision router memory or implement more complex cache eviction policies.