© 2004 Cisco Systems, Inc. All rights reserved. ARCH v Module Summary IP multicast, as an alternative to unicast and broadcast, sends packets to a subset of network hosts simultaneously. By requiring only a single copy of each packet to be sent on each interface, multicast helps reduce network traffic. Multicast deployments require three elements: the application, the network infrastructure, and client devices. IOS multicast is highly scalable. Multicast comprises a single content stream that is replicated by the network at branch points closest to viewers.