Date post: | 31-Jul-2015 |
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Internet |
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ISP-friendly Peer-assisted On-demand Streaming of Long Duration Content in BBC iPlayer
Dmytro Karamshuk1, Nishanth Sastry1, Jigna Chandaria2, Andy Secker2
1King's College London, 2BBC R&D
CD-GAIN: EPSRC project in collaboration with BBC R&D, http://bit.ly/cd-gain
iPlayer is popular and growing
Total monthly BBC iPlayer requests across all platforms, since 2009
Introduced in 2005 for 5K users, now covers 50% of the UK population
“iPlayer Usage Effect - A Bandwidth Explosion”http://community.plus.net/blog/2008/02/08/iplayer-usage-effect-a-bandwidth-explosion/
Content Delivery: traditional approach
Install more distributed caches Requires investments
Any alternatives?
Peer-assisted Content Delivery
Content Delivery Network
user
user user
user
useruser
average of 5K users online every sec in the first day after release
5K duplicates every second!!!
Ask users for assistance
CDNs are interested in traffic savings
Content Delivery Network
user
user user
user
useruser
Traffic gain
- volume of traffic downloaded from content delivery nodes- total volume of traffic watched by the userss
u
TT-1=G
Intuition: bigger P2P swarm yields higher gain
CDN user
1
user
2
user
3
P2P is self-scaling Bigger swarms yield higher savings
Analytical Model based on M/M/ Queues
ci= ui r iAverage number of peers online
How much we can offload to peers
Traffic gain is an exponential function of swarm’s capacity
content popularitycontent duration
G c 1 e c
- by Little`s law
How peer-assistance works in real life
… there is a number of obstacle factors they do not address
Huang, Cheng et al. [NOSSDAV’2008] Zhao, Mingchen, et al. [IMC’2013]
Balachandran et al. [IMC’2013]
Obstacle N1: ISP Friendliness
Content Delivery Network
P2P increases egress traffic, impacting bandwidth cost for ISPs, Karagiannis et al. [USENIX’2005]
Traffic savings drop from 87% to 13% if swarms are localized within ISP and city, Balachandran et al.
[IMC’2013]
Obstacle N1: ISP Friendliness
Content Delivery Network
ISP1
ISP2
P2P increase egress traffic, impacting bandwidth cost for ISPs, Karagiannis et al. [USENIX’2005]
Traffic savings drop to 13% if swarms are localized within ISP and city, Balachandran et al. [IMC’2013]
Obstacle N2: Bitrate Stratification
Content Delivery Network ISP2
ISP1 -768Kbps
ISP1 -1.5Mbps
1080p 720p480p
Obstacle N3: Partial Participation
Content Delivery Network ISP2
ISP1 -768Kbps
ISP1 -1.5Mbps Obstacle factors decrease size of swarms
Only 31% signed up for sharing in Akamai NetSession
Zhao, Mingchen, et al. [IMC’2013]
Users - 2.2 M
IP address – 1.3 M
Sessions - 15.9 MLondon, Sep. 2013
Understanding Obstacles with Data-driven Analysis
Two main bitrate formats dominate in over 70% of sessions
1080p
720p480pDealing with Bitrates
Avera
ge B
roadband S
peed
Results of the Simulations
potential traffic gains for popular content are high despite obstacles
G c 1 e c
An episode of Bad Education series, 100K views
How about Unpopular Content?
BECAUSE swarms are small availability is less
An episode of What You Can Eat show, 1K views
G c 1 e c
Savings across Content CorpusTop-5% of the content
corpus accounts for 80% of trafficMost of accesses happen in the
first day after release
Yes, it’s all about very popular content
Conclusions• with peer-assisted delivery savings grow with thedemand and size of the content despite obstacles• we give a closed form solution for traffic gains
• up to 88% of traffic can be saved
• content bundling does not work but caching canboost savings by 23%
G c 1 e c