Since the nineties, SURF has supported IP Multicast within its network. What once started as a special network for this technology, grew into a standard part of the SURF network. However, after decades of use, SURF has decided to phase out IP Multicast. In this blog post I will explain what IP Multicast exactly is, how it was used within SURF in the past, and why the technology must now make way for modern alternatives.

What is IP Multicast?
IP Multicast is a technology that makes it possible to send data from a server to multiple recipients in a scalable way. The server only needs to send the data once, after which the network takes care of the replication to all recipients.

An example of this is the broadcasting of a live lecture to various universities in the Netherlands. Instead of the live video stream being sent multiple times from the source (once for each recipient), it is only sent once via IP Multicast. The network then ensures that the stream is distributed to all affiliated universities. This reduces the required bandwidth and ensures more efficient use of network resources.

Use and applications within SURF
Over the years, this technology has been tested and used in various ways by affiliated institutions. Examples of applications were:

• Sending television channels to student houses.
• Broadcasting webcam images, such as those of the coast of Vlissingen.
• Sending satellite weather images from Germany to the KNMI and universities in various European countries.
  

Why is IP Multicast used less these days?
Although IP Multicast once held great promise, it is increasingly being used less and less due to management complexity and limitations in modern networks. In cloud environments, where networks are often dynamic and virtual, IP Multicast can be difficult to implement. Many networks prefer unicast streaming and Content Delivery Networks because of their greater scalability and flexibility.

Unicast streaming sends separate data streams to each recipient, which requires more bandwidth, but with the increased capacity of modern networks this is no longer a major issue

Why is SURF discontinuing IP Multicast?
None of the old IP Multicast applications are still active, and IP Multicast has not been used on the SURF network for some time. Supporting IP Multicast introduces significant protocol complexity, both for SURF and for the connected institutions.

By phasing out IP Multicast, SURF is simplifying its network protocols. This decision marks the end of an era, but also opens the door to new technologies and enables a less complex migration to a next-generation network in the future.