Multicast sessions can often flood a network, leaving very little bandwidth for other uses. You can avoid flooding your entire network by limiting multicast sessions to specific segments, which can be done in a number of ways, most of which are typically used to enhance network performance. Using VLANs to segment your network and configuring routers or managed switches to not forward multicast traffic are two common approaches. You can also use the ASR multicast configuration file to specify a low time-to-live rate for multicast packets, keeping them constrained in terms of the number of routers across which they will be forwarded.
If you frequently deploy large numbers of workstations, you might even want to isolate a specific VLAN or network segment for multicast use (in cross-platform networks, this VLAN can be used for both Ghost and ASR sessions). If you do major rollouts on only a limited basis (that is, the opening of a new office or the beginning of the school year), you may want to simply do the deployments with workstations in their final locations and let the network be overrun for a few hours. For other more-limited imaging, such as rolling out a few new workstations at a time or using a clean image as a troubleshooting approach for a single workstation, you may want to rely on unicast solutions that don't require so much bandwidth.