After (hopefully) agreeing on what routing, bridging, and switching are, let’s focus on the first important topic in this area: how do we get a packet across the network? Yet again, there are three fundamentally different technologies:
- Source node knows the full path (source routing)
- Source node opens a path (virtual circuit) to the destination node and uses that path to send traffic
- The network performs hop-by-hop destination-address-based packet forwarding.
More details in the Getting Packets Across the Network video.
If you’re working solely with IP-based networks, you’re likely assuming that hop-by-hop destination-only forwarding is the only packet forwarding paradigm that makes sense. That is not true; even today’s networks use a variety of forwarding mechanisms, most of them called some variant of routing or switching.
What exactly is the difference between the two, and what is bridging? I’m answering these questions (and a few others, like what’s the difference between data-, control- and management planes) in the Bridging, Routing, and Switching Terminology video.