Hola Dinis, lastimosamente no tengo las configuraciones utilizadas ya que fueron hechas en dispositivos reales, de todas formas puedes intentar simularlo en GNS3 realizando las siguientes configuraciones:
Problema 1:
Switch 1
vlan 10
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Switch 2
vlan 10
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
interface fastethernet0/2
switchport mode access
switchport access vlan 20
Problema 2:
Switch 1
vlan 10
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Switch 2
vlan 10
shutdown
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Problema 3:
Switch 1
vlan 10
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
interface fastethernet0/2
switchport trunk encapsulation dot1q
switchport mode trunk
Switch 2
vlan 10
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Problema 4:
Switch 1
vlan 10
vlan 20
interface fastethernet0/1
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Switch 2
vlan 10
vlan 20
interface fastethernet0/1
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Problema 5:
Switch 1
vlan 10
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1
switchport mode trunk
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Switch 2
vlan 10
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
switchport trunk allowed vlan 20
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Problema 6:
Switch 1
vlan 10
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1
switchport mode trunk
switchport trunk native vlan 10
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Switch 2
vlan 10
vlan 20
interface fastethernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk
switchport trunk native 1
interface fastethernet0/2
switchport mode access
switchport access vlan 10
Espero te sirva!
Estoy atento a tus comentarios.