The forwarding table of a router contains roughly one IP prefix per local IP subnet and a small number of aggregate IP prefixes that belong to foreign Autonomous Systems (ASes).

The forwarding table of a link-layer switch contains the MAC addresses of all the end-systems and routers from the local IP subnet that are sending (or recently sent) traffic through this Ethernet switch.

The forwarding table of a link-layer switch contains the IP addresses of all the end-systems and routers from the local IP subnet that are sending (or recently sent) traffic through this Ethernet switch.

The forwarding table of a link-layer switch contains all the MAC addresses in the world.