A Modularized Control Plane for BGP

M. Hidell, P. Sjdin, T. Klockar (Sweden), and L. Carr-Motyckova (Czech Republic)


Router architectures, control plane, routing protocol.


The number of new services and protocols required in IP routers is steadily growing. This adds to the complexity of the router control plane and increases the amount of work that has to be performed by the control processor. Accordingly, the trend of augmenting the router functionality has an important impact on control plane performance and robustness. Traditionally, router control software is intertwined into a single complex system in a centralized fashion. In this paper, we put forward a new way to design the control plane, based on modularization of control software into independent modules that can be decentralized to multiple processing elements and executed concurrently. We have applied this design approach on BGP (Border Gateway Protocol), with the main purpose to do an experimental performance evaluation of distributed control plane processing. We find that the time to process and install a large number of BGP routes, for instance during start-up of BGP, can be significantly reduced if the workload is spread over multiple processing units. We also identify several approaches for improving robustness through the use of a modular decentralized control plane. Finally, we demonstrate that such a system can be realized using unmodified open source routing software.

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