Multicast is arguably the most efficient way to stream live video to large audiences. Because it uses a single stream to reach every single viewer on your network, you can stream to an infinite number of viewers only using the bandwidth needed to stream to one viewer.
For example, it takes about 3.5 Mbps to stream video from Microsoft Stream. If you have 10,000 employees, that means you’d need about 35,000 Mbps of bandwidth to reach every employee. If you’re using a multicast eCDN, the amount of bandwidth needed drops down to only 3.5 Mbps (7 if you add a back-up stream for redundancy).
Because multicast is a push-based technology, it does not optimize video on demand. Viewers can only watch videos at the time they’re sent. That’s why it’s ideal for live webcasts or pre-recorded videos you push at a scheduled time for all to watch.