ACTIVE RELIABLE MULTICAST

1. Sender Sender data data data data data data data data data data Receiver Receiver Receiver Receiver Receiver Receiver ACTIVE RELIABLE MULTICAST Moufida MAIMOUR Congduc PHAM Everybody's talking about multicast! Really annoying ! Why would I need multicast for by the way? 224.0.0.0 DVMRP Cepheus Routing distributed computation grid computing distributed database interactive gaming virtual reality environments software distribution Internet push applications videoconferencing, whiteboard video on demand, broadcasting database replications distributed interactive simulations … Hey man! Think about… BGMP CBT IETF PIM-DM SRM Ursa Multicast IP Multicast ARM DyRAM MBone IGMP Plug yourself in the multicast universe!!! Problem Sending same data to many receivers via unicast is inefficient Example Popular WWW sites become serious bottlenecks What is multicast? Not n-unicast from the sender perspective Efficient one to many data distribution Scalable group communications on the Internet The reliability charter Every receiver must correctly get the data! Feedback (ACK or NACK) implosion Replies/repairs duplications Adaptability to dynamic membership changes difficult ACTIVE NETWORKING COMPONENTS IN THE DyRAM PROTOCOL DYNAMIC REPLIER ACTIVE RELIABLE MULTICAST DEFINITIONS Active routers: routers can perform specific processing at the packet or flow level (caching, subcast, NACK aggregation…). Active networking: as opposed to traditional networking, some routers are active. Subcast: repair packets are sent only to the relevant set of receivers. NACK aggregation:duplicated NACK packets are suppressed and only one is sent back to the replier (source or elected receiver). One benefit of active networking is to unload the source from heavy retransmission overheads. The backbone is fast, very fast (DWDM, 10Gbits/s not uncommun), so nothing else than fast forwarding functions. source The active router associated to the source can perform early processing on packets. For instance our DyRAM protocol uses subcast and loss detection facilities in order to reduce the end-to-end latency. 100 Base TX On computational grids, where the end-to-end latency can become critical, DyRAM can significantly increase performances by associating a dedicated active router to a pool of computing resources. active router active router core network Gbits rate A hierarchy of active routers can be used for processing specific functions at different layers of the hierarchy. For instance, having an active router at the nearest location from the source/destination could performs very efficient NACK packets suppression active router 1000 Base FX active router In DyRAM, any receiver can be designated as a replier for a loss packet.The election is performed by the associated upstream active router on a per-packet basis. Therefore several loss recovery trees can co-exist in parallel at a given time. Having dynamic repliers allows for more scalability as caching within routers is not required. active router An active router associated to a tail link performs NACK aggregation, subcasting and the election on a per-packet basis of the replier. Soft states are maintained within routers to enable these specific functions. OUR RESEARCH DIRECTIONS ANALYTICAL STUDIES OF ACTIVE RELIABLE MULTICAST (THROUGHPUT AND DELAY ANALYSIS) SIMULATIONS AND FORMAL VALIDATION IMPLEMENTATION AND PROTOTYPING ACIgrid