Source-Based Path Selection: The Data Plane Perspective

In source-based path selection, the sender chooses the path to the destination from a set of available paths and embeds the forwarding information in the packets. Future Internet proposals have employed this scheme to realize the benefits of source routing without the inherent scalability problems of path computation at the source. Furthermore, to address the security concerns of packet-carried forwarding state, these proposals leverage cryptographic primitives (e.g., Message Authentication Codes) per packet in the data plane. However, the implications on the forwarding performance of these novel routing schemes have not been studied in detail. In this paper, we study the data plane of source-based path selection schemes. We take SCION---a future Internet proposal---as an example and sketch its data plane implementation. We implement a software switch that can forward up to 140 million minimum-sized packets per second (limited by the hardware I/O subsystem) and can achieve line-rate throughput of 120 Gbps.