October 08, 2019
Place Sainte Barbe - BARB 94
Helping the Internet scale by leveraging path diversity by Fabien DUCHÊNE
Pour l’obtention du grade de Docteur en sciences de l’ingénieur et technologie
Since its inception in the 60's, the Internet has evolved from a nationwide network interconnecting a handful of nodes, to a worldwide system interconnecting billion of devices. While the network has dramatically expanded in size, it has also grown in term of adoption. In the age of the Internet of Things, everything and everyone is heavily connected to the interconnected network. This growth came with a cost for service providers: the user's expectation in terms of reliability and performances. To achieve reliability and performance, network operators and engineers designed redundant systems and tried to balance the load across the network's different paths. While adding redundant paths into the network was already a challenge, a greater one awaited: efficiently using them.
This thesis is a contribution to improve different solutions and leverage the path diversity, especially in datacenters and enterprise networks. First, we improve Multipath TCP to make it compatible with current load-balancers, solving a problem that has been hindering its deployment. Furthermore, we show that the same approach enables anycast Multipath TCP services, a major benefit given the difficulty of deploying anycast TCP services. We implement these modifications in the Linux kernel and demonstrate its benefits with several micro-benchmarks.
We also enable network functions that operate on the bytestream rather than on a per-packet basis by extending the implementation of IPv6 Segment Routing. This enables network architects to design end-to-end services as a series of in-network functions. The measurements realized with our implementation in the Linux kernel indicate that our architecture is well suited to support middle-boxes that process bytestreams.
Finally, this thesis leverages eBPF and IPv6 Segment routing to allow transport protocols to benefit from the path diversity in datacenters and enterprise networks. We implement this architecture and shows that eBPF can be used to dynamically change the path used by a TCP ow with IPv6 Segment routing. This enables improvements to transport protocols by allowing their internal state (Round-Trip-Time, loss rate, ...) to influence the path used in the network.
To allow these ideas to have an impact, the contributions of this thesis have been implemented and evaluated. The code is open source and the suggested modifications to the protocols have been standardized by the IETF. These contributions open new perspectives to efficiently use the multi-path networks of the 21th century.
Jury members :
- Prof. Olivier Bonaventure (UCLouvain), supervisor
- Prof. Charles Pecheur (UCLouvain), chairperson
- Prof. Ramin Sadre (UCLouvain), secretary
- Prof. Laurent Mathy (ULg, Belgium)
- Prof. Stefano Secci (CNAM, France)