ukerna cdi trial infrastructure for content delivery steve williams university of wales swansea
TRANSCRIPT
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
15pps15pps
30pps30pps
600Kbps600Kbps
32Kbps32Kbps
• Streaming metrics– Packet loss – critical for some CODECs– Latency & jitter – much less critical– Need to quantify
• Streaming traffic profile…
Streaming bandwidth
Streaming bandwidth - 350Kbs
0
200400
600800
1000
12001400
1600
1 3 5 7 9 11 13 15 17 19
seconds
Kb
ps
…
• 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