Enabling Conferencing Applications on the Internet using an Overlay Multicast
Reviewer: Robert Dugas
The problem dealt with is how to provide for multicast functionality over
the current internet using end-to-end system design principles.
The main idea presented is an End System Multicast wherein multicast functionality has been pushed to the edges.
- Identifies distinguishing characteristics of conferencing applications: performance requirements, gracefully degradable, session lengths, group characteristics, and source transmission layers.
- Provides means for filtering and estimating bandwidth and latency.
Develops various methods for constructing overlays: unicast, random, propagation-delay-only, latency-only, and bandwidth-latency
Although overlay multicast has been studied extensively, the end-to-end scheme proposed here does
seem to represent a realistically implementable scheme given the generalizability sought after
by the authors.
The authors have obviously performed extensive testing and their results are convincing in
The testbed used by the authors might not necessarily be representative of the Internet on the whole.
It is unclear whether their metrics taken will scale well. The authors acknoledge this scope
The general take away seems to be that overlay methodologies can be used effectively on a relatively
small scale to provide multicast service without altering the infrastructure.