OSDI 2000 Abstract
Overcast: Reliable Multicasting with an Overlay Network
John Jannotti, David K. Gifford, Kirk L. Johnson,
M. Frans Kaashoek, and James W. O'Toole, Jr., Cisco Systems
Overcast is an application-level multicasting system that can be
incrementally deployed using today's Internet infrastructure. These
properties stem from Overcast's implementation as an overlay
network . An overlay network consists of a collection of nodes placed
at strategic locations in an existing network fabric. These nodes
implement a network abstraction on top of the network provided by the
underlying substrate network.
Overcast provides scalable and reliable single-source multicast using
a simple protocol for building efficient data distribution trees that
adapt to changing network conditions. To support fast joins,
Overcast implements a new protocol for efficiently tracking the
global status of a changing distribution tree.
Results based on simulations confirm that Overcast provides its added
functionality while performing competitively with IP Multicast.
Simulations indicate that Overcast quickly builds bandwidth-efficient
distribution trees that, compared to IP Multicast, provide 70%-100%
of the total bandwidth possible, at a cost of somewhat less than twice
the network load. In addition, Overcast adapts quickly to changes
caused by the addition of new nodes or the failure of existing nodes
without causing undue load on the multicast source.
- View the full text of this paper in
HTML form, and
- If you need the latest Adobe Acrobat Reader, you can download it from Adobe's site.
- To become a USENIX Member, please see our Membership Information.