!! Router config !!
en
conf t

int g0/0
 no shut
exit

int g0/0.10
 encapsulation dot1q 10
 ip address 192.168.1.1 255.255.255.0
exit

!! configure g0/0.20 yourself with tag 20 & ip 192.168.2.1

------------------------------------
!! Switch Config

int g0/0
 switchport trunk encapsulation dot1q
 switchport mode trunk
exit
------------------------------------
ping from 1.2 -> 2.2