How do I read your on-line tree?
The bandwidth values on each link are the bandwidth the child
is getting from its parent. Links that are in use are colored in
black. If a node leaves the end system multicast group, the link
that existed between that node and its parent is colored in red.
We update the figure once every minute. If you try to reload more
often, you may not see any changes. Also, if the new figure
changes drastically from the previous figure, this does not
neccessarily mean that the multicast tree has gone through a huge
change. We use dot, a graph visualization tool, to draw the
tree, and dot is not optimized for incremental changes.
You may also notice that the reported bandwidth received by a
parent node may be less than the bandwidth received by a child.
This is because the bandwidth estimation at each receiver is not
synchronized, and the source rate is varying over time.
If I want to broadcast content, why should I use End System
Multicast? Why not use IP Multicast or a content deliver
network (CDN)?
End System Multicast does not rely on dedicated infrastructure
support. While support from infrastructure can be exploited when
available to provide better performance, such support is not
essential for normal operation. Further, no changes are required
at the IP or routing layer.
IP Multicast requires changes to the IP layer, and support from
routers. Deployment of this architecture has proved to be very
difficult. Content delivery networks require dedicated,
provisioned infrastructure support that may not make economical
sense to all users.