Residential Broadband, Second Edition

IP Multicast

IP Multicast is what makes push mode data work over point-to-point networks. In particular, it reduces signaling. It also reduces data volume and tends to synchronize reception of common data flows to multiple receivers. These are useful—even necessary—characteristics for mass market network services.

In the hybrid fiber coax and wireless cases, broadcasting of data is a natural consequence of the physical medium. In the point-to-point wired case, multicast, a software technique that replicates packets efficiently, achieves broadcasting of data. Multicast is more difficult to implement than broadcast because it must track who will and who won't receive packets. Broadcast simply assumes that everyone within receiving range should ...