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The Akamai Network: A platform for
high-performance Internet application
Erick Nygren, Jennifer Sun, Akamai Technologies
Vasileios Pappas, Akamai Technologies and University of Massachusetts
ACM SIGOPS 2010
Speaker : Conque, Kim
[email protected]
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Outline
• Introduction
• Overview of the Akamai platform
• Akamai HD network
• Conclusion
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Introduction
• Possible risks of the current Internet for businesses
• Reliability
– Designed as best effort network, the Internet provides no
guarantees on end-to-end reliability
– Single one-hour outage can cause significant damage to brand reputation of
e-commerce companies
• Performance
– Inherent limitation in the Internet makes difficult to achieve
desired levels of performance for accessing the commercial sites
– e.g. application adoption and site conversion rates
• Large-scale distributed computing platform is needed
• First-pioneered one is the Akamai network
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Problem about performance
• For supporting web content and streaming media, current
network has a limitation
• The distance between server and end user becomes a bottleneck
for video throughput
Distance
Network RTT
Typical
packet loss
Throughput
4GB DVD
download time
Local
1.6 ms
0.6 %
44 Mbps
12 min.
Regional
16 ms
0.7 %
4 Mbps
2.2 hrs.
Crosscontinent
48 ms
1.0 %
1 Mbps
8.2 hrs.
Multicontinent
96 ms
1.4 %
0.4 Mbps
20 hrs.
[Fig] Effect of distance on throughput and download time
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Akamai network
• One of the world's largest distributed
computing platforms
• Feature of the Akamai
• Delivery network for evolving the business network
– First pioneering the concept of Content Delievery Network
– Replicating and delivering content and applications at the edge
of the Internet, close to the end users
• Virtual network for the existing Internet
– Working over the existing Internet as-is
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Benefits of Akamai
• Speed up remote user application performance
• Reduce server load
• Improve application delivery reliability
• Reduce bandwidth usage
at main server datacenter
• Improve application security
[Fig] Global performance with and without Akamai
*borrowed from ADCAP Network system`s site
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Outline
• Introduction
• Overview of the Akamai network
• Akamai HD network
• Conclusion
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Backup Slides
The Akamai EdgePlatform:
105,000+
Servers
1900+
POPs
950+
Networks
750+
Cities
78+
Countries
Resulting in traffic of:
5.4 petabytes / day
790+ billion hits / day
436+ million unique clients IPs / day
* POP : Point of presence
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Anatomy of a delivery network
www.naver.com/image.jpg
End Users
Transport Sys.
Pull-based caching
Contents
ak.naver.com/image.jpg
Mapping Sys.
Data collection & analysis
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Akamai`s Mapping system
• Main parts of the mapping system
• Scoring system
– Creating current, topological map capturing the state of
connectivity across the entire Internet
– Using equivalent classes of IP address and historic and real-time
data like pings, traceroutes, and etc.
• Real-time mapping
– Creating actual maps used by the Akamai platform to direct end
users based on the scored data
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Outline
• Introduction
• Overview of the Akamai platform
• Akamai HD network
• Conclusion
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Delivery network for high
performance
• Video-grade scalability
• Current network including datacenter and peering points is no
longer sufficient to support
• Solution, ‘IP-layer multicasting’ is no more practical in reality
• Streaming performance
• Multi dimensional and complex streaming performance need
measurements for efficiency
• Stream availability, startup time, highest bitrate and effective
bandwidth are a good metrics for optimizing the network
• Monitoring infrastructure built by Akamai are measuring the
metrics above
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Process of streaming CDN
Encoder
Original File
Set
reflector
Set
reflector
Set
reflector
Edge
reflector
Server
Edge
reflector
Server
Edge
reflector
Server
Streaming
Server
Streaming
Server
Streaming
Server
Subscribe
Multicast
Communication
Entrypoint
Subscribe
Publish
Subscribe
Publish
Publish
Mapping to end users
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Techs. for quality of streaming
• Packet loss recovery
• Collecting traces of packet flows that were at least 1 h long, and
spanning a lots of packets
• By using parity bits for single or multiple streams or using plain
retransmission, they can reduce packets` loss rate
• Adaptive multipath transmission
• Replicating packets originating from a particular entrypoint and
sending across multiple set reflectors to a single edge region
• Modifying the streaming server to provide stream quality
information to the edge reflectors
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Techs. for quality of streaming
• Prebursting
• Delivering a stream to a server at a higher rate than the
encoded rate for the first few seconds of the streaming
session`s life
• Advantages
– Reuse the retransmit
buffers as the prebursting
buffers
– Reduce buffering time
x9
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Outline
• Introduction
• Overview of the Akamai platform
• Akamai HD network
• Conclusion
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Conclusion
• Akamai network uses the cache functionality of edge
node for improving the service of B2B networks
• Akamai has been providing their own technics for
improving the end-to-end network performance, and
now especially on the HD network for live streaming
• Packet loss recovery, multipath transmission, and prebursting
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