Every microsecond counts: tracking fine-grain latencies with a lossy difference aggregator

Many network applications have stringent end-to-end latency requirements, including VoIP and interactive video conferencing, automated trading, and high-performance computing—where even microsecond variations may be intolerable. The resulting fine-grain measurement demands cannot be met effectively by existing technologies, such as SNMP, NetFlow, or active probing. We propose instrumenting routers with a hash-based primitive that we call a Lossy Difference Aggregator (LDA) to measure latencies down to tens of microseconds and losses as infrequent as one in a million. surement can be viewed abstractly as what we refer to as a coordinated streaming problem, which is fundamentally harder than standard streaming problems due to the need to coordinate values between nodes. We describe a compact data structure that efficiently computes the average and standard deviation of latency and loss rate in a coordinated streaming environment. Our theoretical results translate to an efficient ha...

• Type: Conference
• Year: 2009
• Where: SIGCOMM
• Authors: Ramana Rao Kompella, Kirill Levchenko, Alex C. Snoeren, George Varghese
• Keywords: Active Probing, Communications, SIGCOMM 2009, Streaming Problems, Stringent End-to-end Latency