CS 414 - Spring 2008 CS 414 – Multimedia Systems Design
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CS 414 - Spring 2008 CS 414 – Multimedia Systems Design

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CS 414 - Spring 2008 CS 414 – Multimedia Systems Design CS 414 - Spring 2008 CS 414 – Multimedia Systems Design Presentation Transcript

  • CS 414 – Multimedia Systems Design Lecture 15 – Multimedia Transport Subsystem (Part 2) Klara Nahrstedt Spring 2008 CS 414 - Spring 2008
  • Administrative
    • Discussion Section II for MP2 on Monday, 2/18, 2008 (3405 SC), 6pm
    CS 414 - Spring 2008
  • OSI (Open System Internconnection) Layering Standard CS 414 - Spring 2008
  • Network QoS and Resource Management
    • Network QoS parameters:
      • End-to-end delay, jitter, packet rate, burst, throughput, packet loss
    • Establishment Phase Protocol to establish Multimedia Call :
      • Application/user defines QoS parameters
      • QoS parameters are distributed and negotiated among participating parties
      • QoS parameters are translated between different layers
      • QoS parameters are mapped to resource requirements
      • Required resources are admitted, reserved and allocated along the path between sender and receiver(s)
    CS 414 - Spring 2008
  • Negotiation and Translation
    • For negotiation of network QoS we may use
      • Peer-to-peer negotiation and triangular negotiation (if service provider allows for negotiation)
    • Translation between network and application QoS
    CS 414 - Spring 2008
  • Negotiation Protocol (P2P Receiver-Initiated Negotiation – Example1) CS 414 - Spring 2008 Sender (Server) Receiver (Client) time time 0 0 Setup Socket Communication Send User/Receiver requested QoS (video rate 20fps) Wait Requested Video rate (e.g.,20fps) Wait Setup Socket Communication
    • - Receive Requested
    • rate
    • Check with Recorded
    • rate
    • If requested > recorded
    • Then decrease rate, else O.K.
    • Translate QoS param.
    • -Perform Resource
    • Admission/Reservation
    • If admission O.K, else
    • Decrease rate, redo
    • Admission/reservation
    • - Send resulting rate
    Resulting video rate (e.g.,10 fps)
    • - Receive resulting rate
    • -Translate QoS param.
    • Perform admission, If admission O.K, , then Reserve resources, else
    • Decrease resulting rate
    • - Send agreed/final rate
    Wait Final video rate (5 fps)
    • Receive final rate
    • Adjust reservation
    • Start streaming
    Streaming Data at final rate Wait
  • Negotiation Protocol (P2P Receiver-Initiated Negotiation – Example2) CS 414 - Spring 2008 Sender (Server) Receiver (Client) time time 0 0 Setup Socket Communication
    • Get QoS (video rate) from user
    • Translate QoS
    • Perform admission, if admission O.K., then reserve local resources, else decrease requested rate, redo admission/reservation
    Wait Requested Video rate (e.g.,20fps) Wait Setup Socket Communication
    • - Receive Requested
    • rate
    • Check with Recorded
    • rate
    • If requested > recorded
    • Then decrease rate, else O.K.
    • Translate QoS param.
    • -Perform Resource
    • Admission/Reservation
    • If admission O.K, else
    • Decrease rate, redo
    • Admission/reservation
    • Send resulting rate
    • Start streaming
    Resulting video rate (e.g.,10 fps)
    • - Receive resulting rate
    • -Translate QoS param.
    • Adjust reservation if needed
    • Start receiving steam
    Streaming Data at resulting rate
  • Negotiation Protocol (P2P Sender-Initiated Negotiation - Example) CS 414 - Spring 2008 Sender (Server) Receiver (Client) time time 0 0 Setup Socket Comm, get movie name
    • -Get recorded rate as the requested rate from the recorded video file
    • Perform admission, if admission O.K, reserve resources, else decrease rate
    • Send requested QoS (video rate 20fps)
    Wait Requested Video rate (e.g.,25ps) Setup Socket Communication (also send server requested video file/movie name)
    • - Receive requested rate
    • -Translate QoS param.
    • Perform admission, If admission O.K, , then Reserve resources, else
    • Decrease rate
    • - Send agreed/final rate
    Wait Final video rate (20 fps)
    • Receive final rate
    • Adjust reservation
    • Start streaming
    Streaming Data at final rate Wait
  • Example of Translation
    • Consider application QoS (frame size M A , frame rate R A ) and network QoS (throughput B N , packet rate R N )
    • Assume
      • M A = (320x240 pixels, 1 pixel = 8 bits),
      • R A = 10 fps, packet size
      • M N = 4KBytes
    • Application Throughput:
      • B A = M A x R A = (320 x 240 x 8) x 10 = 6,144,000 bps
    • Packet rate:
      • = 190 packets per second
    • Network Throughput:
      • B N = M N x R N = 6,225,920 bps
    CS 414 - Spring 2008
  • Admission Control
    • Throughput QoS parameter maps to bandwidth resource
    • Packet rate maps to scheduling resource
    • Error rate maps to buffer resources
    CS 414 - Spring 2008
  • Bandwidth Admission Test
    • Consider
      • b i – reserved bandwidth for the ‘i’ connection
      • B max – maximal bandwidth at the network interface
    • Admission test (if all connections declare their bandwidth requirements b i at the same time):
      • ∑ (i=1,…n) b i ≤ B max
    CS 414 - Spring 2008
  • Bandwidth Admission
    • Admission Test (if requests come in iterative fashion) :
    • Consider
      • b i alloc – bandwidth already admitted, allocated and promised to connection ‘i’
      • b j req – bandwidth requested by connection ‘j’
      • B avail = B max - ∑ (i=1,..n) b i alloc , where i ≠ j
    • Admission Test:
      • b j req ≤ B avail
    CS 414 - Spring 2008
  • Packet Scheduling Admission
    • At switches/routers – packet scheduling decision needs to be made when admitting new streams of packets
    • Need packet schedulability tests
      • Note that in networking only NON-PREEMPTIVE scheduling exists!!!
    CS 414 - Spring 2008
  • Packet Scheduling Admission CS 414 - Spring 2008 e i – processing of a packet ‘i’ in network node Admission Test: e i ≤ deadline (within a switch) ∑ (i=1,…,n) serve i / (1/r) ≤ 1 serve – packet service time at the processors – constant time due to hardware implementation q_in and q_ou t are variable q = N/ λ (Little Theorem) r – service rate of the switch
  • Network Resource Reservation/Allocation
    • Bandwidth reservation
      • Pessimistic reservation with maximal bandwidth allocation: Given ( M N , R A , and M A )
        • if then
    CS 414 - Spring 2008
  • Pessimistic Resource Reservation (Example)
        • Example: Consider sequence of MPEG video frames of size 80KB, 60 KB, 20KB, 20 KB, 60KB, 20 KB, 20 KB (Group of Pictures I, P, B, B, P, B, B ),
    • Pessimistic frame size calculation:
      • M A = max(80, 60, 20, 20, 60, 20, 20) = 80KB
    • Given video frame rate RA = 20 fps
    • If Given MN = 10 KB (network packet size, e.g., packet size for the transport layer like TCP/UDP), then need to consider bandwidth/ throughput reservation for
      • BN = 10KB x (8 network packets per application frame) x 20 application frames per second= 1600 KB/second = 12800 Kbps
    CS 414 - Spring 2008
  • Optimistic Resource Reservation/Allocation
    • Optimistic reservation considers average bandwidth allocation
    • Given MA, RA, MN, where
    • Then
    CS 414 - Spring 2008
  • Optimistic Resource Reservation (Example)
        • Example: Consider sequence of MPEG video frames of size 80KB, 60 KB, 20KB, 20 KB, 60KB, 20 KB, 20 KB (Group of Pictures I, P, B, B, P, B, B, ),
    • Optimistic frame size calculation:
      • M A = 280/7 = 40 KB
    • Given video frame rate RA = 20 fps
    • If Given MN = 10 KB (network packet size, e.g., packet size for the transport layer like TCP/UDP), then need to consider bandwidth/ throughput reservation for
      • BN = 10KB x (4 network packets per application frame) x 20 application frames per second= 800 KB/second = 6400 Kbps
    CS 414 - Spring 2008
  • Sender-Oriented Reservation Protocol CS 414 - Spring 2008
  • Receiver-Oriented Reservation Protocol CS 414 - Spring 2008
  • Reservation Styles
    • IETF (Internet Engineering Task Force) standard defines three types of reservation styles
      • Wildcard
        • Allows receiver to create a single reservation along each link shared among all senders for the given session
      • Fixed filter
        • Allows each receiver to create a single reservation from a particular sender whose packets it wants to receive
      • Dynamic filter
        • Allows each receiver to create N reservations to carry flows from up to N different senders. This style allows the receiver to do channel switching (similar to TV channel switching)
    CS 414 - Spring 2008
  • Reservation Styles CS 414 - Spring 2008
  • Conclusion
    • Important set of services and protocols for establishment of multimedia calls/sessions
    • Different network technologies adopt different establishment approaches, so one has to dig into the standard protocol to see which
      • Negotiation and translation
      • Admission and reservation protocols/services the standard adopts
    CS 414 - Spring 2008