Multicast Lecture 5 - Delivery of Multimedia Services PDF

Wireless Mobile & Multimedia Networking 7COM1076 Dr Myasar Tabany [email protected] Senior Lecturer School of Physics Engineering and Computer Science (SPECS) ...

Wireless Mobile & Multimedia Networking 7COM1076 Dr Myasar Tabany [email protected] Senior Lecturer School of Physics Engineering and Computer Science (SPECS)  7COM1030 – Multicast and Multimedia Networking } Group communications § Many receivers at the same time § Cooperation & interaction between users } Multicast delivery is essential for § Efficient utilization of network bandwidth (resource) – Compared to multiple unicast connections } Technological challenges for multicast § Reliable Multicast, QoS management, group management, etc Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } One-to-many multicast § Internet TV, webcasting – Webcasting of broadband streaming media § Remote education § Distribution of financial data: stock-ticker } Many-to-many multicast § Teleconferencing § Whiteboard } Current trend § Most of commercial services are based on – One-to-many multicast services § Most of ISPs focus on one-to-many services Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } Classification of multicast applications § Collaborative: teleconferencing § Message streaming: streaming media player § Bulk data transfer: multicast file dissemination Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } Broadband: up to 1-2 Mbps per session § Bandwidth (resource) consuming } Multimedia: audio/voice, video, data } Real-time and live broadcasting: time-critical Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } Typical webcasting system Example: YouTube Multicast Lecture 5 – Delivery of Multimedia Services VOD – Video on Demand  7COM1030 – Multicast and Multimedia Networking Tier 1: User interface Tier 2: Logical process Tier 3: Data storage Application servers are used to service data requests between clients and database. a.k.a. Multi-tier Architecture Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } Replicated unicast § TCP/IP unicast connection to each receiver § Multiple unicast connections for a session } Native IP multicast § Within multicast-enabled networks § Multicast forwarding tree between multicast Routers § IGMP between router and hosts } Hybrid of unicast and multicast § Unicast from Sender and Relay Server: – Over unicast networks § Multicast from Relay Server to Recipients – Within the multicast-enabled networks Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking CP Local Network Internet Local Network Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } Replicated unicasts (current & most) § Easy to employ, but § Bandwidth Consuming in the network § Traffic bottleneck at the sender (contents provider) } IP multicast (ideal & best) § Most efficient in terms of utilization of network resources § But, still much technical challenges to solve § Not fully deployed in commercial Internet } Hybrid of unicast and multicast (realistic alternative) § An realistic alternative delivery scheme § For migration to IP multicast – Based on unicast and multicast Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } Multicast group management § Application-level group management § Session management & membership management } End-to-end multicast transport Application § Layer 4 multicast management Transport § Reliable multicast & QoS management Network – ECTP, IETF RMT, etc Access } Multicast routing in networks § Layer 3 forwarding by routers § Multicast routing protocols – DVMRP, PIM, CBT, etc Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } Reliable multicast § Issues: scalability concerns (error/congestion control) § IETF RMT WG – TRACK (Tree-based ACK) protocol – ALC (Asynchronous Layered Coding) protocol – NORM (NACK Oriented Reliable Multicast) protocol § ITU-T Q.8/17 – ECTP (Enhanced Communications Transport Protocol) } QoS management § QoS negotiations/monitoring/maintenance issues § Working in ITU-T Q.8/17 (ECTP) Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } Session management § Session creation/enrollment § User registration/authentication } Membership management § Active membership monitoring and report § Support of billing/charging model } Status § IETF: SDP/SAP, SIP § ITU-T Q.8/17: GMP (working) Multicast Lecture 5 – Delivery of Multimedia Services  7COM1030 – Multicast and Multimedia Networking } Email: [email protected] } Office: LB218 } Tel: 01707 286206 Multicast Lecture 5 – Delivery of Multimedia Services