What situation in production do we need multicast?

[eigrpy]

What situation in production do we need multicast?  Don't we have other skill to replace it? Anyone can explain? YouTube uses it? Thank you

[balaji.bandi]

suggest to visit this for basic understand of Multicast :

https://networklessons.com/multicast/introduction-to-multicast

[marce1000]

 https://www.cisco.com/en/US/docs/switches/lan/catalyst3850/software/release/3se/consolidated_guide/b_consolidated_3850_3se_cg_chapter_0101000.html#topic_D79687D331A54E588B1E42B79E8F4F0D

 M.

[eigrpy]

understand multicast mechanism. My question is what kind of company use multicast? so far these companies that i work for never use multicast. What special company need multicast? YouTube can use it for a lot users to save a lot bandwidth, but he never use it. Stock market use it, for what? save bandwidth or speed? In addition to stock market use it, any other company use it? 

[marce1000]

 - Practicing multicast can only happen on an Intranet environment in a productive way, because it requires a coordinate effort for switching configuration and support.

 M.

[Joseph W. Doherty]

Possible the most common usage of multicast, within an enterprise, is some form of video streaming application, like IPTV or some form of video presentation that includes many.

Actually, for something like YouTube, across the Internet, multicast is not used.

[Scott Leport]

Probably one that belongs more in the voice / collab forum, but multicast is something that is recommended you have configured on your network if you are using Singlewire Informacast paging, that is the Singlewire server is at the central site and you have phones at your branch site which need to receive notifications, e.g. live record or pre-recorded text messages / announcements etc.

[Sergey Lisitsin]

I have encountered multicast in production only twice throughout my career. Both times it was video streaming. I think 90% of the time it will be video/audio streaming, so content providers might run it. Another 10% would be something like trading, where rate updates are needed on a regular basis and to multiple destinations, may be telemetry. Also, I know that some mass imaging software uses multicast to cast images to the target devices.

[Joseph W. Doherty]

"Also, I know that some mass imaging software uses multicast to cast images to the target devices."

Forgot about that one.  Although when I've seen it used the server and the hosts are usually within the same L2 domain (if not also on a standalone network).  NB: multicast routing isn't needed, because multicast routing on the same L2 domain doesn't need it, although a multicast querier might be desired.