Timing is Everything: Accurate, Minimum Overhead, Available Bandwidth Estimation in High-speed Wired Networks Han Wang, Ki Suh Lee, Erluo Li, Chiun Lin Lim, Ao Tang Hakim and Weatherspoon

Introduction Active end-to-end available bandwidth estimation is important and necessary. Send a train of probe packets through a network path to momentarily congest the bottleneck link.

Introduction Existing methods and tools: Observing the change in the output probing rate/ one-way delay.( Spruce/ Pathload ) Querying every network element along a network path.( sFlow )

Introduction Three significant problems: Intrusive Inaccurate (timestamp) Does not work well with bursty cross traffic. =>MinProbe

Background 10 GbE Physical Layer Idle symbols (/I/) An /I/ takes 700~800 pico-seconds

MinProbe Direct access to /I/ characters from software and in real-time. Using application traffic as probe packets. (N, R, G, D) e.g.(2, 500Mbps, 1.2ns, 48us) send 2 packets/48us, with minimal gap 1.2ns at 500Mbps

MinProbe

Implementation SoNIC, with 2 10GbE ports Extended SoNIC’s capabilities: Packet Filtering and Forwarding Packet Gap Extraction and Manipulation Application Programming Interface

Evaluation

Baseline

Evaluation Traffic

Evaluation Traffic

Evaluation Bursty traffic Exponential moving average

Evaluation In the wild

Evaluation Other hardware

Conclusion MinProbe High-fidelity Sub-nanosecond Minimal-cost Using application network traffic as probe traffic In userspace

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