Multicast Media Streaming: Techniques for Efficiency, Security, And Copyright Protection James Logan CS 525 Dr. Chow

James Logan CS Outline Aggregated Trees – Efficiency Multicast Transition Gateway – Efficiency WHIM: Watermarking Multicast Video with a Hierarchy of Intermediaries – Security and Copyright Protection

James Logan CS Aggregated Trees Two Basic Trees In Multicast Networks: - Source Tree: One root per source, MST algorithm used to maintain branches - Shared Tree: Common root chosen as a rendezvous point to distribute all messages

James Logan CS Aggregated Trees Continued Basic Tree Issues: - Too many trees in the network (Source) - Memory and Processing overhead maintaining bi-directional forwarding states (Source) - Overhead processing for tree creation and reconstruction (Source) - Latency, bottlenecking, and additional hop counts (Shared) Solution: - Aggregated Trees

James Logan CS Aggregated Trees Continued Aggregated Trees - Tree(s) managed by a tree manager mechanism and not the routers themselves - Goal: reduce router memory usage, forwarding state entries, router processing, and bandwidth usage in intra-domain networks.

James Logan CS Aggregated Trees Continued Aggregated Tree Procedure: - Dynamic management mechanism evaluates join request sent by border routers. Determines if the subscription is already available on a tree path. If not it creates a new tree or branch(es). - Tree Manager then assigns a tree the multicast group(s). Multiple groups on one tree path reduces bandwidth and router memory usage. - Messages are encapsulated upon entering the network. The original message is preserved upon encapsulation. This is the key to reducing router processing overhead. - Routers decapsulate the messages to determine forwarding. Management Issue: - Centralized Management Mechanism is seen as a single point of failure

James Logan CS Multicast Transition Gateway - Conceptual mechanism used to support protocol transparency for multicast networks that communicate with other networks with limitations. - Transparency is for multicast to unicast (M2U) and multicast to multicast (M2M) for IPv4 and IPv6 transitioning using the following execution configurations: - IPv6 multicast to IPv6 unicast - IPv4 multicast to IPv4 unicast - IPv6 multicast to IPv6 and IPv4 unicast - IPv4 multicast to IPv6 and IPv4 unicast - 6-to-4 and 4-to-6 multicast

James Logan CS MTG Continued How MTG Process Works – Comprised of two components: Client Connection Manager/Announcement Control and Streaming Relay Mechanism – Client makes request via anycast to MTG(s) based on information obtained from Announcement Control (Capacity/Current Bandwidth etc) – Client selects MTG – Client Connection Manager establishes the connection and maintains it – Streaming Relay Mechanism translates messages based on execution configuration

James Logan CS MTG Continued Concerns with two or more MTGs supporting M2M execution configurations - Identical Configurations: client receives the same data from two different sources - Exact Opposite Configurations: Loopback occurs when one MTG sends out multicast messages and another MTG listening on that group receives it and puts it back into the originating network then originating MTG receives the messages and sends them out again. - Solution: Use RTCP message to let other MTGs know a message transition has taken place. - Scaling: In Large networks with many MTGs, Coordination Servers using P2P communicate with each other to select MTG for the client are needed.

James Logan CS WHIM Watermarking Multicast Video with a Hierarchy of Intermediaries - Augmenting Watermarking process that uses fingerprints for copyrighted and restricted data - Based on a MSTstructure broken into two components - WHIM Backbone: Root to Last Router before client - WHIM Last Hop: Last Router to Client

James Logan CS WHIM Continued Goals of WHIM - Ensuring Robustness in Fingerprinting - Preventing the collusion problem - Asymmetric Fingerprinting to identify individual hosts - Protection Granularity - Logging - Efficiency

James Logan CS WHIM Continued How WHIM Works: - Unique path from source to client is created via MST - Source and all intermediary routers are assigned unique ids (WHIM Backbone) - Last Hop router assigns clients unique ids by either its own method or using public keys (WHIM Last Hop) - As messages flow towards clients intermediary routers concatenate their distinct id to the message to create a watermark - At the last hop the router appends the clients id to the watermark the delivers the message to client

James Logan CS WHIM: Diagram

James Logan CS WHIM Continued Major Issues - WHIM can identify who leaked information but cannot guarantee secure routing Solution - Combine WHIM with Hierarchical Secure Streaming which adds the following functionality - intermediate routers assigned keys via root server - upon client request the root server assigns client key - root server sends client the keys of the routers on its unique path which are encrypted by the previous key starting from the client - data sent from root server is encrypted at each hop then decrypted using the keys sent to the client via the root server

James Logan CS Conclusion Always a tradeoff between a desired service and client and network resources A component’s location in the network can have positive and negative consequences based on its configuration and execution MST algorithm is important to ensure efficiency in a multicast streaming network for the technologies that make use of it

James Logan CS REFERENCES [1]Sumit Rot, John Ankorn, Susie Wee, Architecture of a Modular Streaming Server for Content Delivery Networks, 2003 [2]Chung-Ming Huang, Pei-Chuan Liu, A Ubiquitous 1-to-k Media Streaming Architecture Using the IPv4/IPv6 Multicast Transition Gateway Approach, 2004 [3]Li Lao, Jun-Hong Cui, M.Y. Sanadidi, Mario Gerla, Scalable and Adaptive Multicast Video Streaming for Heterogeneous and Mobile Users, 2005 [4]Jun-Hong Cui, Jinkyu Kim, Dario Maggiorini, Khaled Bousetta, Mario Gerla, Aggregated Multicast – A Comparative Study [5]Aiguo Fei, Junhong, Mario Gerla, Aggregated Multicast: an Approach to Reduce Multicast State [6]Hao-hua Chu, Lintian Qiao, Klara Nahrstedt, A Secure Multicast Protocol with Copyright Protection, April 2002 [7]Paul Judge, Mostafa Ammar, WHIM: Watermarking Multicast Video with a Hierarchy of Intermediaries