@inproceedings{5eac2296ec0d4ab08183399e01b4cad8,
title = "Measuring TCP Round-Trip Time in the Data Plane",
abstract = "We present a data-plane algorithm that passively and continuously monitors the Round-Trip Time of TCP traffic, by matching data packets with their associated acknowledgments and calculating a time difference. Compared with traditional measurement systems based on active probing or measuring only SYN/ACK packets, our algorithm passively produces many samples for long-running connections. This enables network operators to observe abnormal RTT increases, which signal possible security or performance issues in the network, in real-time. To satisfy the stringent memory size and access constraints of programmable switches, our algorithm uses a multi-stage hash table data structure to maintain records for in-flight packets; the records not receiving their acknowledgments are lazily expired and overwritten. We implement our algorithm on a Barefoot Tofino programmable switch. Evaluation using a real-world traffic trace from a 10 Gbps campus network link demonstrates that our solution can accurately capture 99% of available RTT samples, using only 4 MB of data-plane memory.",
keywords = "Data Plane, Hash Tables, Network Monitoring, P4, TCP RTT",
author = "Xiaoqi Chen and Hyojoon Kim and Aman, {Javed M.} and Willie Chang and Mack Lee and Jennifer Rexford",
note = "Publisher Copyright: {\textcopyright} 2020 ACM.; 1st ACM SIGCOMM Workshop on Secure Programmable Network Infrastructure, SPIN 2020 ; Conference date: 14-08-2020",
year = "2020",
month = aug,
day = "10",
doi = "10.1145/3405669.3405823",
language = "English (US)",
series = "Proceedings of the 2020 ACM SIGCOMM Workshop on Secure Programmable Network Infrastructure, SPIN 2020",
publisher = "Association for Computing Machinery",
pages = "35--41",
booktitle = "Proceedings of the 2020 ACM SIGCOMM Workshop on Secure Programmable Network Infrastructure, SPIN 2020",
}