Evaluation of link layer mobility in Ethernet networks

Abstract

Ethernet is the prevalent link layer mechanism in data communication networks. Today, it is used in enterprise and home networks, data center networks, telecommunication networks, and in various industrial deployments. In addition, more and more hosts are becoming mobile, connecting to Ethernet networks via Wi-Fi, or through virtualization solutions in data centers. Unfortunately, the Ethernet protocol suite itself has no generic support for host mobility. In this paper, we evaluate the effects of host mobility in Ethernet networks using real-time emulation. We compare routing bridges, an IETF-driven Ethernet frame forwarding protocol, with our DBridges design. DBridges is an evolution of the routing bridges standard, integrating a one-hop Distributed Hash Tables (DHT) scheme into the protocol. Our solution offers improved scalability characteristics in Ethernet networks, as well as enhanced support for host mobility. Our evaluation shows that while host mobility without any explicit signaling will remain a best-effort service in Ethernet networks, we can significantly improve its efficiency and reliability in certain use cases, while providing improved scalability and safety properties. We also show that while the host mobility support in DBridges suffers from transient forwarding loops, the problem is exceedingly rare in real networks and is mitigated by the base functionality in routing bridges.