IP Forwarding Performance Analysis in the Presence of Control Plane Functionalities in a PC-based Open Router Raffaele Bolla, Roberto Bruschi Department of Communications, Computer and Systems Science (DIST) University of Genoa Via Opera Pia 13, I-16145 Genova, Italy Email: raffaele.bolla, roberto.bruschi@dist.unige.it Nowadays, networking equipment is realized by using decentralized architectures that often include special-purpose hardware elements. The latter considerably improve the performance on one hand, while on the other they limit the level of flexibility. Indeed, it is very difficult both to have access to details about internal operations and to perform any kind of interventions more complex than a configuration of parameters. Sometimes, the “experimental” nature of the Internet and its diffusion in many contexts suggest a different approach. This type of need is more evident inside the scientific community, which often encounters many difficulties in realizing experiments. Recent technological advances give a good chance to do something really effective in the field of open Internet equipment, also called Open Routers (ORs). The main target approached in this paper is to extend the evaluation of the OR forwarding performance proposed in [1], by analyzing the influence of the control plane functionalities. Keywords. Open Router, Linux kernel, IP forwarding performance I. Introduction During the past 20 years, Internet equipment has radically changed many times, to meet the increasing quantity and the complexity of new functionalities [2]. Nowadays, current high-end IP nodes belong to the 3 rd generation, and are designed to reach very high performance levels, by effectively supporting high forwarding speeds (e.g., 10 Gbps). With this purpose, these devices are usually characterized by decentralized architectures that often include custom hardware components, like ASIC or FPGA circuits. On one hand, the dedicated hardware elements improve the performance considerably, while, on the other hand, they limit the level of flexibility. Moreover, with respects to this commercial equipment, it is very difficult both to have access to internal details and to perform any kind of interventions that would require more complex operations than those involved by a configuration of parameters: in this case, the “closure” to external modifications is a clear attempt to protect the industrial investment. In many contexts the “experimental” nature of the Internet and its diffusion suggest a different approach. This type of need is more evident within the scientific community,