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

Evaluation

• Baseline

Evaluation

• Traffic

Evaluation

• Traffic

Evaluation

• Bursty traffic Exponential moving average

Evaluation

• In the wild

1.873.58

Evaluation

• Other hardware

Conclusion

•MinProbe•High-fidelity• Sub-nanosecond

•Minimal-cost• Using application network traffic as probe traffic

• In userspace

Thanks!