Simplifying Datacenter Network Debugging with PathDump

Datacenter networks continue to grow complex due to larger scales, higher speeds and higher link utilization. Existing tools to manage and debug these networks are even more complex, requiring in-network techniques like collecting per-packet per-switch logs, dynamic switch rule updates, periodically collecting data plane snapshots, packet mirroring, packet sampling, traffic replay, etc.
This paper calls for a radically different approach to network management and debugging: in contrast to implementing the functionality entirely in-network, we should carefully partition the debugging tasks between the edge devices and the network elements. We present the design, implementation and evaluation of PathDump, a minimalistic tool that utilizes resources at edge devices for network debugging. PathDump currently runs over a real network comprising only of commodity hardware, and yet, can support a surprisingly large class of network debugging problems. Evaluation results show that PathDump requires minimal switch and edge resources, while enabling network debugging at fine-grained time scales.