What: Pro Audio and STL over Internet and Private IP
When: March 17, 2009 7:00 PM

March’s meeting was a natural follow-up to the very popular "IP-University Lite" presented in November. Broadcasters have shown great interest in next generation audio delivery technologies; moving past ISDN, crowded RF spectrum and other aging STL options. Internet delivered audio has become a viable alternative for remote broadcasting but poor Quality of Service ("QOS") makes a full-time Internet STL solution elusive.

Chris Regan, VP Sales & Operations, Americas APT Technology, discussed professional audio over IP, IP STL implementations over private IP networks, and the latest private IP network options for the broadcaster.

Following dinner and pleasant conversation, the meeting was called to order at 7:15 PM. The meeting began with a short presentation of Chapter business.

  1. Thanks to John Holt and WAMU for hosting our March meeting.
  2. Reminder, meeting notices by e-mail blast and Web site
  3. Encourage survey participation. The board would like to know membership preference for meetings in the evening or mid day; convenient times; convenient locations; relevant presentations.
  4. Certification report by Eric Hoehn.
  5. Brief introduction of our guest: Chris Regan, VP Sales and Operations, Americas, APT.
Featured presentation:
  1. Brief tutorial of IP principles and commercial audio over IP
  2. Why audio over IP?
    • Reasonable cost
    • Flexibility, scaled bandwidth
    • Widespread availability
    • Network efficiency: flexible point-to-point and point-to-multipoint configurations
    • Resource efficiency: consolidation of engineering and IT skills and usage.
  3. Network options for STL
    • Dedicated IP Links: Always on
    • MPLS Links: Private managed network
    • Public Internet: not recommended
  4. Network delivery options for STL
    • Wired
    • Wireless
    • Licensed or unlicensed IP microwave
  5. Planning considerations for IP audio network
    • Select reliability over speed
    • Unicasting, multicasting, or multiple-unicast
    • Protocol selection: RTP; UDP; TCP
    • Service Level Agreements
  6. IP Packet vs. synchronous
    • Encapsulation: routing, algorithm, bit rate, sample rate, payload.
  7. Packet size
    • Large
      • Reduced Jitter
      • Increased delay
      • Greater risk due to lost packet
    • Small
      • Increased Jitter
      • Reduced delay
      • Increased bandwidth
      • reduced risk due to lost packet
  8. Jitter: buffer size vs. network delay
  9. Coding Algorithms
    • Psychoacoustic: MPEG, AAC
      • Potentially high distortion
      • “Lossy”
      • High coding delay
    • ADPCM, non-destructive: APT-X
      • Pattern coding
      • “Lossless”
      • Increased bandwidth
      • Low coding delay
  10. Service Level Agreements
    • Best Effort Service: not guaranteed or recommended
    • Guaranteed QoS metrics
    • Non-QoS metrics specified
    • Scope of service
    • Traffic profile: burst data rate, etc.
    • Monitoring and reporting
    • Administrative and legal.
  11. Backup for IP links
    • Same rules as for traditional STL
    • T-1; ISDN; etc.
  12. Network testing and monitoring options
    • Basic: Ping, traceroute
    • APT IP Connection Verifier
    • Other Software Management solutions
    • APT products include full hardware remote control
  13. Floor opened to questions
    • Commercial products vs. consumer products?
    • EAS?
    • Multicast solutions?
    • International?

Chris also brought several of his products for display and some brochures. This meeting was adjourned approximately 8:45 PM.