vrsyrotiuk@water.waterloo.edu (Violet Syrotiuk) (04/03/89)
DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF WATERLOO
SEMINAR ACTIVITIES
COMPUTER NETWORKS SEMINAR
- Thursday, April 6, 1989
Mr. Peter B. Danzig, of the University of California at
Berkeley, will speak on ``Making Multicast Fast''.
TIME: 3:30 PM
ROOM: DC 1304
ABSTRACT
When many or all of the recipients of a multicast
message respond to the multicast's sender, their
responses may overflow the sender's available buffer
space. Buffer overflow is a serious, known problem of
broadcast-based protocols, and can be troublesome when
as few as three or four recipients respond. We develop
analytical models and techniques that calculate the
distribution of the number of buffer overflows, and we
apply these techniques to make multicast with limited
buffers fast. The common cure for buffer overflow
requires that recipients delay their responses by some
random amount of time in order to increase the minimum
spacing between response messages, eliminate collisions
on the network, and decrease the peak processing demand
at the sender. In our table driven algorithm, the
sender minimizes the multicast's expected latency, the
elapsed time between its initial transmission of the
multicast and its reception of the final response,
given the number of times (rounds) it is willing to
retransmit the multicast. We apply our analytical
results to optimally select each round's timeout. We
demonstrate that multiple round multicasts can be an
order of magnitude faster than single round multicasts.
We will discuss these results and our experience with a
small prototype multicast system.
--
Violet R. Syrotiuk | vrsyrotiuk@water.uucp
Computer Science Dept. | watmath!water!vrsyrotiuk
University of Waterloo | vrsyrotiuk@water.uwaterloo.ca
Waterloo, ON N2L 3G1 | vrsyrotiuk@water.waterloo.edu (or .cdn)