Routing Between Subnets on VLANs
Almost all enterprise networks use VLANs. To route IP packets in and out of those VLANs—or more accurately, the subnets that sit on each of those VLANs—some router needs to have an IP address in each subnet and have a connected route to each of those subnets. Then the hosts in each subnet can use the router IP addresses as their default gateways, respectively.
Three options exist for connecting a router to each subnet on a VLAN. However, the first option requires too many interfaces and links, and is only mentioned to make the list complete:
Use a router, with one router LAN interface and cable connected to the ...