Enhancements to P4TG: Histogram-Based RTT Monitoring in the Data Plane

Fuente: arXiv
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Main Authors: Ihle, Fabian, Zink, Etienne, Menth, Michael
Format: Preprint
Published: 2025
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author Ihle, Fabian
Zink, Etienne
Menth, Michael
author_facet Ihle, Fabian
Zink, Etienne
Menth, Michael
contents Modern traffic generators are essential tools for evaluating the performance of network environments. P4TG is a P4-based traffic generator implemented for Intel Tofino switches that offers high-speed packet generation with fine-grained measurement capabilities. However, P4TG samples time-based metrics such as the round-trip time (RTT) in the data plane and collects them at the controller. This leads to a reduced accuracy. In this paper, we introduce a histogram-based RTT measurement feature for P4TG. It enables accurate analysis at line rate without sampling. Generally, histogram bins are modeled as ranges, and values are matched to a bin. Efficient packet matching in hardware is typically achieved using ternary content addressable memory (TCAM). However, representing range matching rules in TCAM poses a challenge. Therefore, we implemented a range-to-prefix conversion algorithm that models range matching with multiple ternary entries. This paper describes the data plane implementation and runtime configuration of RTT histograms in P4TG. Further, we discuss the efficiency of the ternary decomposition. Our evaluation demonstrates the applicability of the histogram-based RTT analysis by comparing the measured values with a configured theoretical distribution of RTTs.
format Preprint
id arxiv_https___arxiv_org_abs_2507_15382
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Enhancements to P4TG: Histogram-Based RTT Monitoring in the Data Plane
Ihle, Fabian
Zink, Etienne
Menth, Michael
Networking and Internet Architecture
Performance
Modern traffic generators are essential tools for evaluating the performance of network environments. P4TG is a P4-based traffic generator implemented for Intel Tofino switches that offers high-speed packet generation with fine-grained measurement capabilities. However, P4TG samples time-based metrics such as the round-trip time (RTT) in the data plane and collects them at the controller. This leads to a reduced accuracy. In this paper, we introduce a histogram-based RTT measurement feature for P4TG. It enables accurate analysis at line rate without sampling. Generally, histogram bins are modeled as ranges, and values are matched to a bin. Efficient packet matching in hardware is typically achieved using ternary content addressable memory (TCAM). However, representing range matching rules in TCAM poses a challenge. Therefore, we implemented a range-to-prefix conversion algorithm that models range matching with multiple ternary entries. This paper describes the data plane implementation and runtime configuration of RTT histograms in P4TG. Further, we discuss the efficiency of the ternary decomposition. Our evaluation demonstrates the applicability of the histogram-based RTT analysis by comparing the measured values with a configured theoretical distribution of RTTs.
title Enhancements to P4TG: Histogram-Based RTT Monitoring in the Data Plane
topic Networking and Internet Architecture
Performance
url https://arxiv.org/abs/2507.15382