Inter VLAN routing using router-on-a-stick

[giacomo12]

Hello,

I am studying the CCNP switching and I am trying to set Inter VLAN routing using router-on-a-stick  in GNS3

I followed all the commands I need to set to configure this type of topology, but I am getting SVI 2 (Vlan2) down. Where am I wrong?

Below the config of the switch and of the router:

(Vlan1 - Vlan2) Switch (Gi0/0)--------(Gi0/0)Router

Switch#show ver
Cisco IOS Software, vios_l2 Software (vios_l2-ADVENTERPRISEK9-M), Version 15.2(4.0.55)E, TEST ENGINEERING ESTG_WEEKLY BUILD, synced to  END_OF_FLO_ISP
System image file is "flash0:/vios_l2-adventerprisek9-m"

interface GigabitEthernet0/0
 description Trunk_to_router-on-a-stick
 switchport trunk allowed vlan 1,2
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 100
 switchport mode trunk
 media-type rj45
 negotiation auto

.

.

interface Vlan1
 description Vlan 1
 ip address 10.1.1.2 255.255.255.0
!         
interface Vlan2
 description Vlan 2
 ip address 10.2.2.2 255.255.255.0
!        

Switch#show ip int brief
Interface              IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0     unassigned      YES unset  up                    up     

.

.

Vlan1                  10.1.1.2        YES NVRAM  up                    up      
Vlan2                  10.2.2.2        YES NVRAM  down                  down    
Switch#

////////////////

Router:

Router# show ver
System image file is "flash0:/vios-adventerprisek9-m"
Router#

!         
interface GigabitEthernet0/0
 description To_multilayer_Switch
 no ip address
 duplex auto
 speed auto
 media-type rj45
!         
interface GigabitEthernet0/0.1
 description Vlan1
 encapsulation dot1Q 1 native
 ip address 10.1.1.1 255.255.255.0
!         
interface GigabitEthernet0/0.2
 description Vlan2
 encapsulation dot1Q 2
 ip address 10.2.2.1 255.255.255.0

Router#show ip int brief
Interface                  IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0         unassigned      YES NVRAM  up                    up      
GigabitEthernet0/0.1       10.1.1.1        YES NVRAM  up                    up      
GigabitEthernet0/0.2       10.2.2.1        YES NVRAM  up                    up     

Thank you

[Sheraz.Salim]

interface Vlan2
 description Vlan 2
 ip address 10.2.2.2 255.255.255.0

 no shutdown

[Mark Malone · Accepted solution]

Hi
is there an STP instance for vlan 2 in FWD state ?
or is there an access port assigned to vlan 2 and up/up state ?

one of these conditions must be met for a vlan to become operational and up/up , most likely why its down

I dont think no shut will work as its not admin down , its already enabled

[Sheraz.Salim]

@Mark Malonethanks for the clarification. vlan 2 must be assigned to a port in order to come as up/up agree with you. 

[Andrew Khalil · Accepted solution]

Hello @giacomo12,

Greetings,

Just assign any interface to vlan 2 in order to become up:

#int fx/x

#switchport mode access

#switchport access vlan 2

#no shutdown

That's it!

Please don't forget to rate all helpful responses!

Bst Rgds,

Andrew Khalil

[Hulk8647]

he has a trunk allowing vlan 2, he don't need to,

[Hulk8647]

make sure your vlan 2 is in vlan database, if you're running the old version for the IOS on GNS3, from what I can remember, you'll need to add the new vlan to database

Switch#vlan database
Switch(vlan)#vlan 2
Switch(vlan)#exit
APPLY completed.
Exiting....
Switch#

[Richard Burts]

I am not sure that it relates to why vlan 2 is down but I do notice a mismatch in the configuration of switch and router. On the switch the interface is a trunk carrying vlans 1 and 2 and the switch is configured that the native vlan is vlan 100. So both vlan 1 and vlan 2 will be sent as tagged frames. On the router the sub interface for vlan 1 indicates that it is the native vlan so it will be expecting un tagged frames but the switch will be sending tagged frames.

HTH

Rick