VLANs: many networks on one switch

The idea

alice and bob in sales, carol and a build server in engineering, all plug into one Switch, officeSwitch. VLANs split it into networks that cannot hear each other; officeRouter, a Router, joins them on purpose.

Steps

1. A card for each VLAN

   Here the split lives on the devices' cards, so read alice's card, then the router's.

   alice:~# ip -d link show eth0.10
   alice:~# ip -br -4 addr show
   officeRouter:~# ip -br -4 addr show

2. The tag inside the frame

   Alice pings bob, in her VLAN, starting with an ARP broadcast. Alice, and carol (VLAN 20) on her cable and on her VLAN card, record it, to find where the tag sits and who hears it.

   alice:~# ping -c1 -W2 10.0.10.11