Maybe a mention of other, non-ethernet, links. Serial PPP? Frame Relay? I realize these are mostly historical curiosities these days, but it might help to enforce the differences between L2 and L3.
When I first started working with routers, over 25 years ago, it was all ethernet LAN to serial WAN, usually point-to-point T1 or frame relay. On site had a dual T1, load balanced on both ports of a Cisco 2501. Fun times.
When I first started working with routers, over 25 years ago, it was all ethernet LAN to serial WAN, usually point-to-point T1 or frame relay. On site had a dual T1, load balanced on both ports of a Cisco 2501. Fun times.