1. Sharing Social Content from Home: A Measurement-driven Feasibility Study Massimiliano Marcon Bimal Viswanath Meeyoung Cha Krishna Gummadi NOSSDAV 2011 11/4/20151 MPI-SWS KAIST

2. Growth of social content Social content includes personal photos, videos, status updates – FB: 15 billion photos, 220 million weekly uploads Huge growth due to rising popularity of social networks Social content is often personal, users want control over: – What they share: – Whom they share with (access control, privacy) – How the content is being used (e.g. advertising) 11/4/20152

3. How is social content shared today? User generates content Content is uploaded to datacenter (e.g. Facebook) Datacenter delivers content via traditional Web – Web servers, CDNs 311/4/2015

4. Good side of current content sharing Performance and availability – OSNs use well-provisioned servers – Content accessible 24/7 from everywhere OSNs are storing content for users 411/4/2015

5. Bad side of current content sharing Restrictions on what / how much can be shared – Content type and quality Loss of ownership / copyrights – Terms of service of OSNs are complex – They may include broad rights on content, typically: Loss of privacy – OSNs privacy policies are complex, may change at any time – If malicious, OSNs can infringe on users’ privacy 511/4/2015 “worldwide, non-exclusive, royalty-free, sublicenseable and transferable license to use, reproduce, distribute, prepare derivative works of, display, and perform the Content” (YouTube, Facebook, Flickr) Users lose control over their data

6. Idea: What if we shared content from home? Assume you serve your content from a server in your home Bad side of current content sharing goes away: – No restrictions on what can be shared – No loss of ownership No terms of use with third parties – Access control managed at user’s homes Independent of third parties’ privacy policies What about the good side of current content sharing? 611/4/2015 Personal home server

7. Can we preserve the good side? Users must now store their content – Idea: use cheap commodity storage Availability may decrease – Idea: use a cheap always-on residential gateway Performance may decrease – Because bandwidth of residential links is limited – Observation: personal content has often limited audience Cost – Example: Residential gateway + 1TB disk ≅ $140 one time cost (Amazon prices) – For comparison: 1TB/month on Amazon S3 = $95/month 11/4/20157

8. This talk Is it feasible to share social content from home? – Characterize OSN workloads (Flickr/YouTube) – Characterize home network environment – Evaluate feasibility of content delivery from home 11/4/20158

9. Understanding OSN workloads Datasets Gathered Flickr: – 11,715 randomly chosen users – 1.3M public photos – Observed views received by photos for 19 days YouTube: – 77,575 randomly chosen users – 1.2M public videos – Collected views received by videos for 166 days Goal: understand how users upload and view content 911/4/2015

10. How much content do users upload? Avg. total uploaded data: 13.3MB Flickr 103MB YouTube Very few users have >10GB Shared photos/videos can easily fit in commodity storage 1011/4/2015 Users by uploaded content

11. How popular is the content? Social workloads are not too demanding Never requested in 1 week: 97% of Flickr pics 50% of YouTube videos 94% of videos <100 views 90% YouTube users serve <7.6GB/week = 100Kbps Demands for Flickr much smaller 1111/4/2015

12. This talk Is it feasible to share social content from home? – Characterize OSN workloads (Flickr/YouTube) – Characterize home network environment – Evaluate feasibility of content delivery from home 11/4/201512

13. Characterization of home networks Configured home routers to gather measurements Deployed them in 10 households (EU & Korea) Collected 79 days worth of data about: – Availability of gateways and local devices – Spare capacity of access links – Performance of content delivery Goal: estimate availability and performance 11/4/201513 USB Storage WLAN port

14. Availability of gateways/devices Gateways periodically send heartbeat messages – If no messages arrive in 5 min, gateway is disconnected Content delivery from gateways provide high availability Availability results Gateway average98% Local device average27% 1411/4/2015

15. How much spare capacity in access links? 11/4/201515 Gateways monitored utilization of access links – Recorded total upstream and downstream traffic values 80% of the time, upstream link is not used 95% of the time, upstream traffic less than 15Kbps

16. This talk Is it feasible to share social content from home? – Characterize OSN workloads (Flickr/YouTube) – Characterize home network environment – Evaluate feasibility of content delivery from home 11/4/201516

17. Performance of content delivery (photos) Every 10 minutes, gateways fetch 20 60KB photos – From Facebook – From a randomly chosen gateway among the home gateways Photo delivery times PercentileFacebookTestbed 50 th 0.36 sec1.91 sec 80 th 0.81 sec2.91 sec 95 th 1.38 sec5.32 sec 1711/4/2015 Performance generally acceptable for browsing Photo prefetching could improve it considerably

18. Performance of content delivery (videos) Every hour, gateways fetch an 18MB video – From Facebook – From a randomly chosen gateway in the testbed – Every second, throughput is recorded to simulate streaming Can we support delivery of streaming content? 1811/4/2015

19. Is there sufficient bandwidth for streaming content? 95% of the time, avg. bandwidth higher than 200Kbps 66% of the time, avg. bandwidth higher than 400Kbps Pre-buf. helps for high quality audio and YouTube-like bit-rates. 11/4/201519

20. Conclusions Social content sharing is very popular on OSNs – Current architectures results in loss of control over data Can we share social content from home? – Characterized social workload on Flickr/YouTube Volume of uploaded content easily fits on commodity storage A lot of content is never requested A lot of content is unpopular Estimated potential for home-based content delivery – Home gateways provide high availability – Promising for personal photos, and low bit-rate media 11/4/201520

21. Interesting future directions How to deal with high-quality media? – Idea: friends could help you deliver your content – Prefetching content could improve performance How to deal with very popular content? – Idea: They can be served from centralized infrastructure 11/4/201521