telecom italia group ongoing activities report ti @ bt london, feb 15, 2011
TRANSCRIPT
TELECOM ITALIA GROUP
Ongoing Activities Report
TI @ BTLondon, Feb 15, 2011
Topics► Application-Layer Traffic Optimization► Video Traffic Optimization► AOB
TI @ BTOngoing Activities Report
Application-Layer Traffic Optimization
TI @ BTOngoing Activities Report
Application-Layer Traffic Optimization in IETF
► Protocol for exporting network topology information
► Assist application in selecting the hosts they can connect to
► Peer-to-peer
► File sharing: find close and well connected peers
► VoIP: find close and fast relays
► P2P Streaming: find close, fast and well connected stream sources
► CDN: find close cache servers
► Protocol ~80% done
► Discussion on REST-like/REST-full approach
► Security
► Protocol interoperability event in July
► Demo show in March
TI @ BTOngoing Activities Report
ALTO Protocol – Ranking Service
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ALTO Protocol – Maps and Ranking Combined
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Opensource ALTO Client (for Vuze)
Design Goals
► Provide a knob for influencing peer selection
► Peer connect
► Optimistic unchoke
► Provide a framework for collecting statistics
► Extensibility
► Different logics/protocols
► Different stats collection strategies
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http://code.google.com/p/bass-plugin/
TI @ BTOngoing Activities Report
Traffic Localization Study (from Telefonica)
► “Deep Diving into BitTorrent Locality”, R. Cuevas et al., INFOCOM 2011
► Research activity going on since 2008
► Extended study on 100K torrents, 3.5M peers, 9K ASes
► Experimental validation
► Italy ≠ Spain ≠ UK
► Inherent language localization
► Uplinks
► Proposed localization model
► Traffic savings at locality/QoS breakthrough point varies between 10% and 35%
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Video Traffic Optimization
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HTTP Video Streaming Optimization
► HTTP-based streaming
► Youtube and the like, Apple HTTP Live Streaming…
► ~40% (steadily growing) of total mobile traffic
► Optimization Strategies
► Smart buffering
► Compression
► Re-encoding, transcoding, transrating, resizing
► Dynamic bitrate adaptation
► May make sense on mobile
► 3G dongle and smartphones
► Resources for compression cheaper than radio link
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TI @ BTOngoing Activities Report
Internal Trial – Three solutions
► Technical evaluation
► Optimization (compression, smart buffering…)
► Codecs support
► Content detection
► Transparency
► Caching
► Configurability
► Quality evaluation
► Focus group
► Outcome
► Technology roughly mature
► 30% to 50% reduction in video traffic
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TI @ BTOngoing Activities Report
Savings Estimation
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WARNING: what follows is a simplified model for savings estimation elaborated over the eight weeks trial period. It is based on rough assumptions that, to the least, need to be double checked with real data
TI @ BTOngoing Activities Report
Savings Estimation – Assumptions
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Definition Bitrate Acceptable
Compression
Frequency(3G
dongles)
Low Resolution
(240p)360x240 200 Kbps 10% 15%
Mid Resolution
(360p)480x360 800 Kbps 40% 80%
High Resolution
(720p)
1280x720
2000 Kbps 60% 5%
TI @ BTOngoing Activities Report
Savings Estimation – Compression
► Average bitrate:
► 200 * 15% + 800 * 80% + 2000 * 5% = 770 Kbps
► Average bitrate after compression:
► 200 * 15% * 90% + 800 * 80% * 60% + 2000 * 5% * 40% = 451 Kbps
► Savings on video traffic due to compression:
► 1 - 451 / 770 = ~40%
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TI @ BTOngoing Activities Report
Savings Estimation – Smart Buffering
► More assumptions
► Users watching a video switch after 20 seconds on average
► Available bandwidth on average: 900 Kbps
► Average video bitrate: 770 Kbps (derived above)
► Data downloaded for each video:
► 20 sec * 900 Kbps = 2.1 MB
► Data downloaded for each video with smart buffering:
► 20 sec * 770 Kbps = 1.8 MB
► Savings on video traffic due to smart buffering:
► 1 - 1.8 / 2.1 = ~14%
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TI @ BTOngoing Activities Report
Savings Estimation – Overall
► Data downloaded for each video:
► 20 sec * 900 Kbps = 2.1 MB
► Data downloaded for each compressed video with smart buffering:
► 20 sec * 451 Kbps = 1.1 MB
► Total savings on video traffic:
► 1 – 1.1 / 2.1 = ~47%
Note Well: Savings are referred only to video traffic delivered by HTTP streaming (e.g. YouTube, Facebook…), reportedly accounting for about 25% - 50% of the total Internet traffic
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TI @ BTOngoing Activities Report
Savings Estimation – Simulations
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Low Res Frequency
Mid Res Frequency
High Res Frequency
Available Bandwidt
h
Watch Time
Savings on Video
15% 80% 5% 900 Kbps 20 sec 50%
20% 75% 5% 800 Kbps 10 sec 46%
30% 65% 5% 500 Kbps 10 sec 19%
10% 70% 20% 1200 Kbps 30 sec 57%
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Possible Issues
► Legal
► Net neutrality
► Agreements requirements
► Complexity/Reliability
► Technology evolution
► Protocols, codecs, encryption
► Popularity shift
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AOB
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CDN Interoperability
► BoF in Prague
► Interface for CDN interwork
► Request routing
► Metadata exchange
► Logging
► Orthogonal to ALTO
► CDN usage for ALTO to pick the closest cache
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TI @ BTOngoing Activities Report
SIP-XMPP Coexistence
► Combined SIP-based VoIP and XMPP-based presence
► XMPP has wider adoption than SIP SIMPLE
► PSTN interoperability is based on SIP
► SIXPAC WG proposed last year
► Virtual PBX for SME
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TI @ BTOngoing Activities Report
Other IETF Work
► RTP extension for audio levels in conference calls
► P2PRG
► ISDN UUI in SIP (booooring!)
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