Multicast for CATV Distribution


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Multicast for CATV Distribution

  1. 1. Multicast for CATV Distribution Alan Crosswell Columbia University Ivy+@Duke May '05
  2. 2. Contents <ul><li>Overview of IP Multicast </li></ul><ul><li>SD/HD Quality Video Bandwidth Requirements </li></ul><ul><li>Decoders & Encoders </li></ul><ul><li>Campus Multicast Routing </li></ul><ul><li>LAN Multicast </li></ul><ul><li>Internet Multicast Routing </li></ul><ul><li>Rights Management </li></ul><ul><li>Licensing Content </li></ul>
  3. 3. Overview of IP Multicast <ul><li>For each channel, only one copy of the stream is sent, with routers “forking” it as needed to reach only interested viewers. </li></ul><ul><li>The transmitter sends just one stream no matter if it's 1 or 1000 viewers. </li></ul><ul><li>Compare to unicast streaming (e.g. Real, Quicktime or Windows Media) where your servers and network have to scale up linearly with the number of viewers. </li></ul><ul><li>N.B. “Live” transmission only; not VoD. </li></ul>
  4. 4. Unicast vs. Multicast Multicast Unicast from Internet2 Multicast Workshop
  5. 5. Video Bandwidth Requirements <ul><li>Standard Definiton: “D1” 720x480 </li></ul><ul><ul><li>MPEG-2: about 5 Mbps </li></ul></ul><ul><ul><li>mJPEG (DV): about 30 Mbps </li></ul></ul><ul><li>High Definition: 1080p </li></ul><ul><ul><li>MPEG-2: about 270 Mbps </li></ul></ul><ul><li>Typical campus residence network speeds: </li></ul><ul><ul><li>Cat 3 Ethernet 10 Mbps </li></ul></ul><ul><ul><li>Cat 5+ Ethernet 10/100/1000 Mbps </li></ul></ul>
  6. 6. Decoders <ul><li>Set-top box or PC viewer? </li></ul><ul><ul><li>Northwestern is using Videofurnace PC viewers </li></ul></ul><ul><ul><li>Dartmouth also using Videofurnace. </li></ul></ul><ul><ul><li>Cornell is using PC viewer and Amino STB with encryption hardware/software </li></ul></ul><ul><ul><li>Is the “TV set” obsolete? </li></ul></ul>
  7. 7. Software Decoders <ul><li>Many software viewers available, depending on the encoding </li></ul><ul><ul><li>Videofurnace </li></ul></ul><ul><ul><li>Cisco IP/TV Viewer (obsolete?) </li></ul></ul><ul><ul><li>Vbrick Streamplayer </li></ul></ul><ul><ul><li>Videolan Client (VLC; MPEG licensing issues) </li></ul></ul><ul><ul><li>Windows Media, Quicktime, etc. </li></ul></ul>
  8. 8. Set Top Decoders <ul><li>Amino </li></ul><ul><li>i3 </li></ul><ul><li>2wire </li></ul><ul><li>Bast </li></ul><ul><ul><li>Info from Dov Zimring, Occam Networks </li></ul></ul>
  9. 9. Encoders <ul><li>What is the source? </li></ul><ul><ul><li>Analog: Vbrick, Tandberg, Videofurnace, VLC, etc. </li></ul></ul><ul><ul><li>DVB: </li></ul></ul><ul><ul><ul><li>Minerva </li></ul></ul></ul><ul><ul><ul><li>Skystream </li></ul></ul></ul><ul><ul><ul><li>Tut Systems </li></ul></ul></ul><ul><ul><ul><li>Bigband Networks </li></ul></ul></ul><ul><ul><li>Stored files (campus TV) </li></ul></ul><ul><li>MPEG->Analog->MPEG or directly use the MPEG from the DVB? </li></ul>
  10. 10. Billing, provisioning, etc. <ul><li>Myrio </li></ul><ul><li>Minerva </li></ul><ul><li>Infogate </li></ul>Info from Dov Zimring, Occam Networks
  11. 11. Campus Multicast Routing <ul><li>Routing protocols to implement: </li></ul><ul><ul><li>PIM-SM - router-to-router </li></ul></ul><ul><ul><li>IGMP - host-to-router </li></ul></ul><ul><ul><li>MBGP – multicast reachability (used by PIM-SM) </li></ul></ul><ul><ul><li>MSDP – multicast source discovery for inter-domain multicast </li></ul></ul><ul><li>These are all widely supported today on modern campus routers (e.g. Cisco, Juniper) </li></ul><ul><li>There are issues on some other vendors' boxes. </li></ul>
  12. 12. LAN Multicast <ul><li>Today's biggest problem area for high-bandwidth stream distribution. </li></ul><ul><li>“ Old school” broadcast LAN model floods multicast traffic out all switch ports. </li></ul><ul><li>IGMP snooping switches solve this, but: </li></ul><ul><ul><li>Be sure they support IGMP version 3 </li></ul></ul><ul><ul><li>Invest the time and effort in evaluating competing products. </li></ul></ul><ul><li>See </li></ul>
  13. 13. Internet Multicast Routing <ul><li>Not much extra work is required to extend your multicast campus to the multicast Internet. </li></ul><ul><li>A good source/sink for non-commercial TV programming? </li></ul><ul><ul><li>ResearchChannel - </li></ul></ul><ul><ul><li>Open Student TV Network </li></ul></ul><ul><li>See: </li></ul><ul><ul><li> </li></ul></ul>
  14. 14. Rights Management <ul><li>IP Multicast does not intrinsically support viewer tracking (which is why it scales so well!). </li></ul><ul><li>How do you track views of premium channels? </li></ul><ul><ul><li>Encryption </li></ul></ul><ul><ul><li>Application-specific methods for retrieving the encryption key </li></ul></ul><ul><ul><li>? </li></ul></ul>
  15. 15. Licensing Content <ul><li>Cornell: Time Warner is peering with the campus network and supplying MPEG-2 streams. A fixed fee per head was negotiated with TW. This service is Cornell-branded. </li></ul><ul><li>Northwestern: ? </li></ul><ul><li>Dartmouth: Adelphia (120 channels) </li></ul>