1. CD-GAIN: Content Delivery
Through the Analysis of Users' Access Patterns
Dmytro Karamshuk1, Nishanth Sastry1, Jigna Chandaria2, Andy Secker2
1King's College London, 2BBC R&D
CD-GAIN: ESPRC project in collaboration with BBC R&D, http://bit.ly/cd-gain

2. CISCO Visual Networking Index
Some Figures
• Video traffic in 2013 accounted for 66% of all traffic
on the Internet and is predicted to reach 79% by 2018
• Nearly three-fourths of the world’s mobile data traffic
will be video by 2019

3. …which Raise Some Issues
User Experience Carbon Footprint
Business Models

4. Users - 32 M/month
IP address – 20 M/month
Sessions - 1.9 Billion
May 2013 – Jan 2014
≈ 50% of the UK population
First-mile view of the UK’s IP-ecosystem
2 x [INFOCOM’2015], [WWW’2013]

5. Where the market is heading?
Fixed-line Internet market
(5 representative providers)
Mobile market is more dynamic than the fixed-line Internet market
Mobile Internet market
(5 representative providers)

6. Pricing Models
All-you-can-eat data
(M1, M5)
Limited-cap data packages
(M2 – M4)
All-you-can-eat plans boost
users consumption
Users of all-you-can-eat data
providers are more “loyal”

7. Behavioral Shift
• Fixed-line accesses (F1-F5) peaks in the evening
• Limited data caps (M2-M4) peak in commute hours
Mobile users watch more
during commutes
• Unlimited plans (M1, M5) is a superposition of both

8. Product Bundles
Inter-ISP attractiveness: normalized fraction of shared users
between a pair of mobile and fixed-line ISP
Product bundles can be used to share infrastructure between
peaking in non-intersecting time periods mobile and fixed-line ISPs
Combinations of ISPs
corresponding to existing
product bundles

9. Limitations to mobile-fixed interactions
Correlation of content
popularity across different ISPs
Share of accesses
per content genre
User of mobile and fixed-line ISPs watch slightly different content

10. More on Infrastructural Support
Regional activity levels are correlated with the access speed
Solution: let’s install more distributed caches!!!

11. Content Delivery: traditional approach
Install more distributed caches Requires investments
Increased carbon footprint

12. Peer-assisted Content Delivery
Content Delivery
Network
user
user user
user
user
user
average of 5K users online every sec in the first day after release
5K duplicates
Ask users for assistance

13. P2P: Obstacles
Bitrate Stratification
Partial Participation
ISP friendliness
1080p
720p
480p

14. Dealing with Obstacles
Five biggest ISPs account for over
80% of traffic
Two main bitrate formats
dominate in over 70% of sessions
Traffic fragmentation by ISP and bitrate formats
yields few large content swarms

15. Traffic Savings and Swarm Capacity
Traffic gain:
- volume of traffic downloaded from content delivery nodes
- total volume of traffic watched by the users
potential traffic gains for popular content are immense despite constraints
Swarm capacity: c
G 1
Ts
Tu
- average number of users online

16. A Simple Theoretical Model
model the system as an infinite servers queue
CDN user
1
user
2
user
3
intuition: the more users in a swarm
the more savings

17. Higher Demand means Higher Savings
ci
=ui
riAverage number of peers online
G(c)=1−(
c(1+e
c
c
−m
(mΓ(m)−Γ(1+m,c)))
m
+1)
−1
How much we can offload to peers
Traffic gains are growing with
the demand and the size of content
request ratemean session duration
G c 1 e
c
Particularly, if m=1:

18. Theory VS Simulations
Theory is in a good agreement with simulations

19. Savings across Content Corpus
Top-5% of the content
corpus accounts for 80% of traffic
Most of accesses happen in the
first day after release
Yes, it’s all about very popular content
https://vimeo.com/99054874

20. How about Unpopularity Content?
Content Bundling Client Caching
Pro-active pushing VS reactive pulling?

21. Client Caching
client caching can boost gains for up to 20%
Improv. in a single swarm Improv. for the content corpus

22. Carbon Footprint
number of hops = 5-7 number of hops = 3
Traditional content delivery network Peer-assisted CDN
Number of networking nodes powered to delivery a video
in peer-assisted scenario is potentially smaller

23. Potential Energy Savings
Average distance between peers
in a swarm with a given capacity
Energy savings for a swarm
with a given capacity
peer-assisted content distribution may lead to energy savings

24. Conclusions
• there is substantial difference in accesses patterns between fixed-
line ISPs, mobile ISPs with all-you-can-eat data and limited data-
caps
• this difference can be effectively exploited in shared mobile-fixed
infrastructures
•user engagement depends on the level of infrastructural support
• with peer-assisted delivery savings grow with demands even
despite obstacles
• peer-assisted CDN can also be green

25. Dmytro Karamshuk
King's College London
follow me on Twitter: @karamshuk
Our website:
http://bit.ly/cd-gain