When to Use a Multicast eCDN

Learn more about multicast.

Enterprises have relied on the stability and scalability of the multicast protocol for delivering video inside the enterprise for decades. One of three core eCDN technologies, multicast is by far the most efficient way to stream video to hundreds, thousands and even tens of thousands of viewers. But like its eCDN counterparts, multicast has relative strengths and weaknesses.

If any of the following network environments or streaming use cases describe your enterprise, multicast is probably your best choice for an eCDN.


You have a multicast network

First and foremost, your network needs to be multicast enabled to use this type of eCDN. Not all networks have multicast “turned on”, but this is a prerequisite for using a multicast eCDN.

Multicast is a fundamental part of IP networks today. Used mostly for link-local service discovery, it works well, is well understood and requires little network treatment.

If only parts of your network are multicast enabled, you can use video caching and/or P2P (peer-to-peer) networking to distribute video to the other parts of your network.

Live events are a priority

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.

Security is paramount

It goes without saying, security is a top priority in all things IT—and video is no different. A survey conducted by Wainhouse Research at the end of 2019 found 68% of those surveyed responded “maintaining network security” is “very important” when asked about the most important factors playing into their streaming video purchase decisions.1

But security goes well beyond what’s built in to your streaming platform. You need to look at your entire streaming solution from soup to nuts. For example, are you opening up your firewall to access a cloud-based eCDN solution? If so, you’re exposing your entire network to potential hackers. With a multicast eCDN, it remains 100% behind your firewall.

For more, read our recent blog about why eCDN security matters. 

Network stability and predictability

By far the strongest advantage of multicast is that a single segment of video is only sent once on any given WAN, LAN or Wi-Fi segment, making it highly deterministic.

A 4 Mbps video never consumes more than 4 Mbps on every segment of the entire network—even as the number of viewers grows. Whether you’re streaming in standard definition, HD or 4K, you can predict with absolute certainty the impact your next live event will have on your network.

You use Wi-Fi

Many organizations are turning to Wi-Fi to keep employees productive wherever they work in the office. Every commercial-grade (and most consumer-grade) access points support unicasting of multicast traffic.

Simply configure your Wi-Fi connection points for multicast, then you’ll be able to predict the amount of bandwidth needed to send a consistent, high-quality stream over your wireless network (equal to one or two viewers). Note, a P2P eCDN can actually double the amount of bandwidth consumed through your wireless access points.


Choosing the right eCDN

Multicast is just one of the three main types of eCDN technologies on the market today. You can also consider video caching, P2P networking or a combination of all three eCDN solutions. Each has its own inherent strengths, weaknesses and network considerations.

To learn how each eCDN works, key deployment considerations and pros and cons of each, download Protect Your Network from Streaming Video: Guide to Selecting the Right eCDN.

1 Survey Insight: Enterprise Video, ITDM Perspectives – North America Q3 2019, Wainhouse Research