Measuring YouTube Content Delivery over IPv6 - IETF [PDF]

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IPv6 traffic largely dominated by YouTube [2]. 2009 2010 2011 2012 2013 2014 2015 .... //mailman.nanog.org/pipermail/nanog/2016-January/083624.html. [2] N.
Measuring YouTube Content Delivery over IPv6 Vaibhav Bajpai TU Munich

Motivation Methodology Success Rate

IETF 99 Prague, CZ Published at: SIGCOMM Computer Communication Review July 2017: https://goo.gl/oUJ7Ej

IPv6 Preference TCP connect times Startup Delay Throughput Stall Events

Joint work with

Recommendations Q/A

Saba Ahsan Aalto University, Helsinki, Finland Jörg Ott TU Munich, Germany Jürgen Schönwälder Jacobs University Bremen, Germany July 2017 1 / 18

Motivation Google IPv6 Adoption

▶ IPv6 contributes ∼25% [1] of traffic within Comcast. ▶ Swisscom reports ∼60% [1] of IPv6 traffic is YouTube. ▶ IPv6 traffic largely dominated by YouTube [2].

20% 15% 10% 5% 0%

Motivation Methodology Success Rate 2009 2010 2011 2012 2013 2014 2015 2016 2017

shaded region represents the duration of the longitudinal study.

Do users experience benefit (or suffer) from YouTube streaming over IPv6?

IPv6 Preference TCP connect times Startup Delay Throughput

NETWORK TYPE RESIDENTIAL NREN / RESEARCH BUSINESS / DATACENTER OPERATOR LAB IXP

RIR

∼100 dual-stacked SamKnows probes (∼66 different origin ASes)

RIPE ARIN APNIC AFRINIC LACNIC

# 78 10 08 04 01

Stall Events Recommendations Q/A

# 60 29 10 01 01

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Research Contribution Motivation Methodology



HE (RFC 6555) makes clients to prefer streaming YouTube videos over IPv6.



Observed performance (both in terms of latency and throughput) over IPv6 is worse.



Stall rates are low, bitrates that can be reliably streamed are comparable.



When a stall occurs, stall durations over IPv6 are higher.



Worse performance is due to GGC nodes that are IPv4-only.

Success Rate IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A

This is the first study to measure YouTube content delivery over IPv6

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Methodology | Selection of YouTube Videos Motivation Methodology



Using YouTube v3 API [3].



Video Selection Criteria:

Success Rate IPv6 Preference TCP connect times

1. Video duration > 60s. 2. Available in Full HD. 3. No regional restrictions. ▶

List updated every 12h.



Probes daily pull the list.



The test supports non-adaptive and step-down playout modes only.



Results are biased our vantage points (centered largely around EU, US and JP).

Startup Delay Throughput Stall Events Recommendations Q/A

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Success Rate Motivation

Success Rate

The test executes once every hour (over both AF).

Methodology Success Rate

IPv6 (102)

IPv6 Preference

1.0 0.8 0.6 0.4 0.2 0.0

['14 - '17]



Number of successful iterations to total iterations. CCDF



1.0 0.8 0.6 0.4 0.2 0.0

IPv4 (102)

TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A

80%

85%

90%

95%



99% of probes achieve success rate of more than 94% over IPv4.



97% of probes achieve success rate of more than 94% over IPv6.



Slightly lower success rates over IPv6 due to network issues closer to probes.

100%

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IPv6 Preference Motivation

1.0 0.8 0.6 0.4 0.2 0.0

Methodology

['14 - '17]

CCDF

IPv6 Preference Web (871) Audio (871) Video (871) 95%

96%

97%

98%

99%

100%

Success Rate IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations



RFC 6724 [4] makes apps prefer connections made over IPv6.



RFC 6555 [5] allows apps to fallback to IPv4 when IPv6 connectivity is bad.



TCP connections over IPv6 are preferred at least 97% of the time.

Q/A

Clients prefer streaming YouTube videos over IPv6 6 / 18

TCP connect times Motivation Methodology

1.0 0.8 0.6 0.4 0.2 0.0

Success Rate

['14 - '17]

CDF

TCP connect times Web (6.5M) Audio (6.5M) Video (6.5M)

−100

−75

−50

−25 ∆t (ms)

0

25

50

IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A



63% of a/v streams (and 72% of the web connections) are slower over IPv6.



14% of a/v streams are at least 10 ms slower over IPv6.

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TCP connect times Motivation

∆t (ms)

∆t (ms)

TCP Connect Times

Methodology

0

Success Rate IPv6 Preference

Web −5

0.0 −0.1 −0.2 −0.3 −0.4

TCP connect times

TCP Connect Times

Startup Delay Throughput

Audio Video

Stall Events Recommendations

Jan 2015

Jul

Jan 2016

Jul

Jan 2017

Jul



TCP connect times consistently higher over IPv6 and have not improved over time.



TCP connect times towards the webpage worse over IPv6 than towards media servers.

Q/A

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Sequence Diagram (contd.) Motivation Methodology Success Rate IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A

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Startup Delay Motivation Methodology

1.0 0.8 0.6 0.4 0.2 0.0

Success Rate

['14 - '17]

CDF

Startup Delay 6.5M

−5

−4

−3

−2 −1 ∆s (s)

0

1

IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A



80% of the samples are slower over IPv6.



Half of the samples are at least 100 ms slower over IPv6.

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Startup Delay Motivation Methodology Success Rate IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A



Prebuffering durations are ∼25 ms higher over IPv6.



Startup delays are ∼100 ms higher over IPv6.



Initial interaction with the web server makes startup delay worse over IPv6. 11 / 18

Sequence Diagram (contd.) Motivation Methodology Success Rate IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A

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Throughput Motivation

Video (6.5M) Audio (6.5M)

−4

∆tp (MB/s)

['14 - '17]

CDF

Throughput 1.0 0.8 0.6 0.4 0.2 0.0

−2

0 ∆tp (MB/s)

2

4

Success Rate IPv6 Preference TCP connect times Startup Delay Throughput

Throughput

0.2 −0.1 −0.4 −0.7 −1.0

Methodology

Stall Events Recommendations

Video Jan 2015

Jul

Jan 2016

Jul

Audio Jan 2017

Q/A Jul



80% of video and 60% audio samples achieve lower throughput over IPv6.



The throughput is consistently lower over IPv6, but it has improved over time. 13 / 18

Sequence Diagram (contd.) Motivation Methodology Success Rate IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A

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Stall Rates Motivation

1.0 0.8 0.6 0.4 0.2 0.0

Methodology Success Rate IPv6 Preference

['14 - '17]

CDF

Stall Rate

IPv6 (102)

1.0 0.8 0.6 0.4 0.2 0.0

IPv4 (102)

TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A

0%

5%

10%

15%

20%

25%

30%



90% of the probes witness less than 1% stall rate over both address families.



Bitrates reliably streamed is also comparable over both address families. 15 / 18

Stall Durations Motivation Methodology

1.0 0.8 0.6 0.4 0.2 0.0

Success Rate

1.7K −60

−40

−20 0 ∆st (s)

20

40

['14 - '17]

CDF

Stall Durations

60

IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A



80% of samples experience stall durations that are at least 1s longer.

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Recommendations Motivation



Update RFC 6555 with a lower HE timer value. ▶

We have shown [6] that reducing HE timer value to 150 ms (from 300 ms) helps.

Methodology Success Rate IPv6 Preference

0.10%

W6LD

0.15%

W6D

0.20%

6to4/Teredo Decline

TCP connect times Startup Delay Throughput

0.05%

Stall Events

0.00% 2009 2010 2011 2012 2013 2014 2015 2016 2017

Recommendations Q/A



ISPs should put latency as a first-class citizen.



ISPs should ensure GGC nodes are dual-stacked. ▶

Request an IPv6 prefix allocation from Google.

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Takeway Motivation



Clients prefer streaming YouTube videos over IPv6.



Observed performance (both in terms of latency and throughput) over IPv6 is worse.



Stall rates are low, but when a stall occurs, stall durations over IPv6 are higher.



Worse performance due to GGC nodes that are IPv4-only.

Methodology Success Rate IPv6 Preference TCP connect times Startup Delay Throughput Stall Events



Reproducibility Considerations: ▶

The test is open-sourced: https://github.com/sabyahsan/youtube-test



The dataset is released: https://github.com/vbajpai/2017-ccr-youtube-analysis

Recommendations Q/A

www.vaibhavbajpai.com [email protected] | @bajpaivaibhav 18 / 18

References [1] NANOG. (2016) IPv6 traffic percentages? [Online]. Available: https: //mailman.nanog.org/pipermail/nanog/2016-January/083624.html

Standard), RFC Editor, Fremont, CA, USA, pp. 1–32, Sep. 2012. [Online]. Available: https://www.rfc-editor.org/rfc/rfc6724.txt

[2] N. Sarrar, G. Maier, B. Ager, R. Sommer, and S. Uhlig, “Investigating IPv6 Traffic - What Happened at the World IPv6 Day?” ser. Passive and Active Measurement Conference, 2012, pp. 11–20. [Online]. Available: https://doi.org/10.1007/978-3-642-28537-0_2

[5] D. Wing and A. Yourtchenko, “Happy Eyeballs: Success with Dual-Stack Hosts,” RFC 6555 (Proposed Standard), RFC Editor, Fremont, CA, USA, pp. 1–15, Apr. 2012. [Online]. Available: https://www.rfc-editor.org/rfc/rfc6555.txt

[3] G. Developers. (2017) YouTube Data API. [Online]. Available: https://developers.google.com/youtube/v3/docs/videos/list

[6] V. Bajpai and J. Schönwälder, “Measuring the Effects of Happy Eyeballs,” ser. Applied Networking Research Workshop, 2016. [Online]. Available: http://dl.acm.org/citation.cfm?id=2959429

[4] D. Thaler, R. Draves, A. Matsumoto, and T. Chown, “Default Address Selection for Internet Protocol Version 6 (IPv6),” RFC 6724 (Proposed

Motivation Methodology Success Rate IPv6 Preference TCP connect times Startup Delay Throughput Stall Events Recommendations Q/A

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