The Advantages of Switches Over TCP

The key advantages of using switches is that the switches are doing the copying in specialized hardware, which is just fundamentally faster than you can do on your own machine. When you make available a multicast stream, there's this distributed algorithm that runs on the switches where it learns essentially what we call the multicast tree. And then those switches know which part they need to forward packets to. So if you have like 12 recipients in some distant network, you can send one to the local switch. The final copying happens at the last layer at the place where it's most efficient.