UKERNA CDI TrialInfrastructure for Content Delivery
Steve WilliamsUniversity of Wales Swansea
Focus on issues in deployment now…
but keep the vision in mind.
Previously on streaming…
• Commercial sector– Cable TV– Video on Demand, live broadcast– Dedicated, secure, purpose built networks
• Academic sector– Local distribution of local and other content– Distribution splitting of live content (SURFNet 2500
viewers)– No caching of on-demand content– Multi-service, multi-purpose, multi-administrative-
domain networks– Some commercial providers just don’t get it!
Design and deploy an extensible, standards-based architecture that is scaleable to the needs of the
UK academic community
Scaleability
• 10 Gigabit SJ4 & GÉANT– 1500 high quality video streams (7Mbps MPEG-
2)– Coleg Gwent has 30,000 students!
• SJ4 now connects HE, FE and Schools – how many…– close your eyes and think of a big number – dark isn’t it – All want video – yesterday!– Access-link limitations (FE-England 2Mbps)
• Server farms not enough– Content is never where you want / expect it to be– Need to use network resources efficiently
Transport options
• Multicast– Yeah, right! I really do wish…
• Simulated / partial multicast / unicast– Proxy-based live-stream splitting– Proxy-based on-demand caches
Server farm
Institution proxyand cache
Clients
SJ4
Software
• Kasenna Mediabase XMP SE– Running on IRIX and Linux– Commercial CDNetworks, on-demand & live cable-nets
via set-top boxes etc (e.g. Kamas, Utah…)– Prefix caching
• Real Networks– Helix Universal Internet Server– Helix Universal Gateway– Running on Linux
• Monitoring– Cisco SAA– mySQL & scripts
Hardware
• Core– SGI Origin 300 + TP900 storage pack– Dell 2950
• Edges– Sun LX50 (3 x 70GB)– Dell 2900 (6 x 73GB)– Origin 300 + TP900
• 1.5 Terabytes content storage available• Monitoring
– Cisco 805 / 7206
Deployment issues
• Use MPEG-2 and MPEG-4• Mediabase now only supports one MPEG-2 plugin• So use MPEG-4 only… (seen as the future by most)• Issues in caching MPEG4 on Mediabase
– Caching does not work at all in XMP SE (bug fix soon?)
– MPEG 4 seen as the future for most CD across Europe
• Caching MPEG2– Realtime mode only– Prefix caching works
Hosting Server
• Scaled to suit distribution model– Processor– Network– IO throughput– Disk size– O/S– Licensing may affect choices (per server – per
site)
Network requirements
• Depends on distribution model• To QoS or not to QoS…• Videoconferencing metrics
– Packet loss < 0.25%– Jitter < 30ms– Latency (OWD) < 50ms
• Videoconferencing traffic profile…
Example of 384 Kbps Video (30 fps) Conferencing Traffic (CIF)
• “I” frame is a full sample of the video• “P” and “B” frames use quantization via motion vectors
and prediction algorithms
“P” and “B” Frames128–256 Bytes
“I” Frame1024-1518
Bytes
“I” Frame1024-1518
Bytes
15pps
30pps
600Kbps
32Kbps
• Streaming metrics– Packet loss – critical for some CODECs– Latency & jitter – much less critical– Need to quantify
• Streaming traffic profile…
Streaming bandwidth
Streaming bandwidth - 350Kbs
0200400600800
1000120014001600
1 3 5 7 9 11 13 15 17 19
seconds
Kbps
…
• QoS– Impact of applying QoS AF-PHB on an
aggregated tcp / udp transfer stream– Sizing the AF bandwidth– tcp backoff under congestion within the
aggregate
Kasenna Mediabase XMP
SE in Reading C-PoP
Quicktime ClientsDirect Delivery from Mediabase
Kasenna Mediabase XMP
SE inReading C-PoP
Kasenna MediabaseXMP SE atInstitutions
Quicktime Clients
SJ4
Proxy / Cache Delivery from mediabase
Helix Universal Internet Server
Helix UniversalGateway
Quicktime & RealMedia Clients
SJ4
Proxy / cache delivery from Helix
SJ4
Monitoring the netmySQL server
Cisco SAA
Cisco SAA
Cisco SAA
Cisco SAA
Cisco SAA
Cisco SAA
Cisco SAA
Web server
Steve WilliamsUniversity of Wales Swansea