An Evaluation of Opportunistic Native Multicast

Hybrid multicast opportunistically combines Application Layer Multicast and native multicast protocols. This paper presents an evaluation of Opportunistic Native Multicast which uses the AMT multicast tunnelling protocol. We describe our opportunistic multicasting approach that tries to solve the islands phenomenon by building unicast tunnels to connect these islands while attempting to utilise the native multicast capability of the islands. It is expected that this hybrid approach will improve both efficiency and availability of multicast. We compare our approach to the ALM protocol SCRIBE. The comparison here was done using five metrics: Stress, Stretch, intra-island traffic, interisland traffic and Delivery rate. In all of them, our proposed model has shown improved results over ALM. Moreover, we investigated what effect the number of islands that the receivers are distributed into, has on performance

A simulation model for hybrid multicast

In order to achieve one-to-many data delivery on the internet, native multicast is used and implemented in some parts of the Internet. On the other hand, application layer multicast (ALM), which uses P2P overlays (overlay multicast, OM), can be used to create multicast trees and deliver the data at the application layer. Despite Native Multicast being more efficient than Application Layer Multicast, it is not deployed widely. A hybrid multicast protocol has been proposed that opportunistically combines overlay multicast protocols and native multicast protocols to create and maintain hybrid multicast trees. The design for hybrid multicast trees leverages the AMT multicast tunneling protocol. It is expected that this hybrid approach will improve both efficiency and availability of multicast. This paper presents a simulation model for the Oversim/Omnet++ simulation framework to evaluate the performance of the hybrid multicast approach. Our model combines both a scalable overlay and a detailed network layer model that includes routers with native multicast support

Performance Analysis of Protocol Independent Multicasting-Dense Mode in Low Earth Orbit Satellite Networks

This research explored the implementation of Protocol Independent Multicasting - Dense Mode (PIM-DM) in a LEO satellite constellation. PIM-DM is a terrestrial protocol for distributing traffic efficiently between subscriber nodes by combining data streams into a tree-based structure, spreading from the root of the tree to the branches. Using this structure, a minimum number of connections are required to transfer data, decreasing the load on intermediate satellite routers. The PIM-DM protocol was developed for terrestrial systems and this research implemented an adaptation of this protocol in a satellite system. This research examined the PIM-DM performance characteristics which were compared to earlier work for On- Demand Multicast Routing Protocol (ODMRP) and Distance Vector Multicasting Routing Protocol (DVMRP) - all in a LEO satellite network environment. Experimental results show that PIM-DM is extremely scalable and has equivalent performance across diverse workloads. Three performance metrics are used to determine protocol performance in the dynamic LEO satellite environment, including Data-to- Overhead ratio, Received-to-Sent ratio, and End-to-End Delay. The OPNET® simulations show that the PIM-DM Data-to-Overhead ratio is approximately 80% and the protocol reliability is extremely high, achieving a Receive-to-Sent ratio of 99.98% across all loading levels. Finally, the PIM-DM protocol introduces minimal delay, exhibiting an average End-to-End Delay of approximately 76 ms; this is well within the time necessary to support real-time communications. Though fundamental differences between the DVMRP, ODMRP, and PIM-DM implementations precluded a direct comparison for each experiment, by comparing average values, PIM-DM generally provides equivalent or better performance