The main difference is that 'ports' live under the protocol layer (TCP/UDP/...) - TCP port 22 and UDP port 22 are not in the same address space In many way's i

The main difference is that 'ports' live under the protocol layer (TCP/UDP/...) - TCP port 22 and UDP port 22 are not in the same address space In many way's it's a very historical thing, back when TCP/IP was one of many competing network architecture (early 80s) most of the competing architectures did it the other way (there was only one port at that level and protocols ran under that). Is one better than the other? probably not much - TCP/IP won (IMHO) because they understood datagrams vs. virtual cicuits - they didn't plan on charging for TCP or IP level retries.