A new hybrid HTTP/UDP protocol is proposed to optimize over-the-top (OTT) video delivery. It uses a combination of HTTP/UDP transport, forward error correction, and advanced congestion control to improve startup times, sustained bitrates, and reduce rebuffering compared to traditional monolithic HTTP delivery. Initial lab tests show improvements like half the startup time, 2-5x higher bitrates, and 10x fewer rebuffers. The protocol could also support multicast delivery when appropriate network conditions allow for it. The hybrid approach aims to maximize throughput while preventing packet loss and latency from negatively impacting the viewing experience.

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Maximizing the Pipe: Hybrid
Protocols for Optimized OTT
Delivery
Will Law | Chief Architect | Akamai

2. 2
http://www.akamai.com/60seconds

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Video quality problems hurt our customers
 Viewers start to abandon a video if it takes more
than 2 seconds to start up
• Playback failures like re-buffering result in less video
consumed
 Users are particularly sensitive to:
• Startup time
• Sustained bitrate
• Re-buffer time

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Problems due to poor network conditions
 What do poor network conditions look like:
• Packet loss is > 1%
• Latency is > 100ms
 Why does this happen:
• Home network routers
• Geographically remote users
• Cellular connections

5. Network conditions by country
TCP re-transmission rates, as sampled by our edge servers

6. Monolithic delivery
 95% of OTT content today is delivered via
unicast HTTP over TCP
 UDP offers higher throughput, but it does
not natively correct for packet loss or
congestion
 How can we improve this????
#multinetwork #IBCShow

7. The solution: A new Hybrid HTTP/UDP
Protocol
 This new protocol prevents packet loss and
latency from impacting the video viewing
experience by using:
• Hybrid HTTP/UDP Transport Protocol
• Forward Error Correction
• Advanced Congestion Control
#multinetwork #IBCShow

8. Astraeus Hybrid HTTP/UDP research
 HTTP/UDP Hybrid Protocol
• Transparent, reuses existing
infrastructure
 Advanced Congestion Control
• Based on FastTCP, can provide
further improvements due to
flexibility of UDP
 Forward Error Correction (FEC)
• Raptor10 FEC
Initial Results
• ½ the startup time
• 2x – 5x the bit rate
• 10x fewer rebuffers
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9. Astraeus – how would it be deployed?
 Implemented on each Akamai edge server
 SDKs for iOS, Android, Desktop, *.STB
App layer integration.
Service layer
integration.
Connected Device Stack
OS
Services / Libraries
Application Framework
App
Astraeus SDK
Astraeus SDK
Standard HTTP
App
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10. Astraeus impact – initial lab test results
These results show
TCP Reno
FastTCP
Astraeus
compared against
certain sample network
conditions under a
controlled lab
environment
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11. Could we make it mo’ better?
 We’re still unicasting with Astraeus - albeit
more efficiently
 What if we added the ability for that same
client software to receive multicast streams
if appropriate?
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Multicast delivery – Requirements
 Be compatible with existing media players such
as Apple HLS player on iOS (i.e deliver segmented
media to the app layer)
 Must support Automatic Multicast Tunneling
(AMT) in addition to native IP multicast
 Support existing Akamai streaming features such
as Media Encryption and DVR
 Transparent fallback -> unicast Astraeus ->
unicast TCP

13. Summary – Hybrid Client Protocol Stack
#multinetwork #IBCShow
TCP unicast
UDP unicast
UDP multicast
}
Smart clients which can
switch smoothly
between hybrid delivery
protocols for optimized
OTT delivery

14. Does this stuff actually
work?
#multinetwork #IBCShow

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Thank You
Visit us at #6.A15
Will Law
www.akamai.com