This article presents a survey of architectures, techniques, and algorithms
for multicasting data in communication switching networks. We start with a
broadcast architecture using a separate copy network and a routing network
. A few versions of this idea using Delta and Benes networks exist. Another
multicast architecture is a recycling network where internal nodes act as
relay points, accept packets from the switching fabric, and recycle them ba
ck into the fabric after relabeling the packets. Next, we give an overview
of a system that uses the Boolean splitting multicast algorithm. In this sy
stem a nonblocking self-routing broadcast Banyan copy network has been prop
osed. The network consists of several components including a running adder
network to generate running sums of copy numbers specified in the headers o
f input packets. We then describe a multicasting technique presented for a
different class of switching networks called deflection-routing networks. F
inally, the idea of extending a nonblocking network to a three-dimensional
structure consisting of multiple parallel planes is also presented. At the
end of this article, we compare the efficiencies of the presented multicast
architectures.