FMNC – Fast Mobile Network Characterization

FMNC – Fast Mobile Network Characterization

Lixing Song, Aaron Striegel{lsong2,striegel}@nd.edu University of Notre Dame

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Problem Statement

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+Sensors

Bodycams

How can we longitudinally test what the network performance would look like in practice?

Problem Statement

• Determine WiFi quality– At this moment

∘ Which way should my traffic go?∘ Which SSID / AP is best?∘ Is this WiFi performance acceptable?

– Longitudinally∘ Check my WiFi performance

– Every 15 minutes, 10 minutes, 5 minutes, 1 minute

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Available Throughput

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SpeedTest.netiperf

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AB (Available Bandwidth) vs. AT (Available Throughput)

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SpeedTest = AT AB is the floor for AT

Available Bandwidth (AB)

• Measure packet dispersion– PathChirp, Spruce, WBest+

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Packet Rate Model:

Pack

et R

ate

Packet Gap Model:

tPa

cket

Siz

et

Frame Aggregation (802.11e)

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Without frame aggregation

Data Data Data

Block Ack

With frame aggregation

DataSender

Receiver Ack

Data

Ack

Data

Ack

Can we capture the “bursts” of queuing toinfer the presence of aggregation?

Frame Aggregation vs. AB

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Gaps become spiky. Rates become bimodal!

Aggregation Index - AI

• Capture the degree to which packets are aggregated

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𝑢𝑢𝑥𝑥 is the bandwidth utilization;𝐺𝐺𝑠𝑠𝑠𝑠𝑠𝑠 isthe sending packet gap;

When we exceedAB with our probing,

AI will spike

Experimental Validation

8/2/2018 Lixing Song, Ph.D. Oral Candidacy 10

𝐺𝐺𝑠𝑠𝑠𝑠𝑠𝑠 fixedProbe traffic causes 0.1link utilization.

Design Principles - FMNC

• Zero client modifications– Work within existing protocols / stacks

∘ TCP/IP, HTTP GET

• Fast Energy / Impact to other flows– Less than 250 ms resolution time

• Accurate in zone that matters– 0-11 Mb/s - Red, Yellow, Green– Can trigger alternate tests

• Lightweight– Less than 100 KB of data

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Sliced, Structured, Reordered Packets

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Experimental Setup

• Client– Periodic FMNC web gets (Android phone)

• Server– Custom libpcap-based server

• Wireless links– 802.11n

• Cross Traffic– UDP via clients sharing same wireless

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Results - Estimations

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Performance

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802.11n2.4 GHzUDP controlled links40 ms RTT

Performance – Classification

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Deployment

• ND spring break– Incentivized participation

∘ NetHealth study (500)∘ Approx. 100 unique devices

– Client for FMNC∘ AirWatch∘ Android Play Store Beta∘ Throughput test + FMNC

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Data Summary

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HighlightsAverage B/W

20.38 Mb/sResolution Time

239.8 ms (90th Percentile)

Bandwidth Cost250x savings vs. iperf

Fast Mobile Network CharacterizationDiscussion - AT&T – June 17, 2016Energy: 2.18 mAh for iPerf (10s) vs. 0.003 mAh for FMNC

Example Result (Simple HTML Output)

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Questions?

striegel@nd.edu

Fast Mobile Network Characterization

Supported in part by NSF CNS-1718405