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Dr Evil

Can't configure port on ISR 1100

When I try to configure the interface omn G0/1/0

R1(config)#int g0/1/0
R1(config-if)#ip address
% Invalid input detected at '^' marker.

Which indicates that the command is not right, but it is and I can't change the status to up when I configure no shutdown.

I know it's physical connected port , but I'm happy for any suggestions on what the issue can be, thanks.

Kevin Martin

On the ISR 1100's, the G0/1/X interfaces are switchports by default.  The Router interfaces are G0/0/0 and G0/0/1.  

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So we have the need to route information between our local LAN and two branch offices that are connected to us via EPL (ethernet private line).  We have no encryption or anything on those private lines.  I have 2x1921s currently in the main location, one for each branch, and we bought a ISR 1111-4P to replace both 1921's.  Are you saying this router only has 2 routeable/assignable ports on it?  If so I'm going to have to send it back and find something else.

Hello @ADynes ,

you can use SVIs on the L2 ports so you can have more then two subnets connected to them




if the switchports support trunk you can go over two SVIs in these two ports.


Hope to help



Hi @Giuseppe Larosa ,


Maybe I'm missing something but that post didn't seem to answer my issue.  For example right now:


Cisco 1921 at (HQ) -> Routes to /16 (Branch A)

Cisco 1921 at (HQ) -> Routes to /16 (Branch B)


I am trying to replace both 1921's with a single ISR 1111.  I can assign Gigabit 0/0/0 and 0/0/1 to do the routing but how do I assign a LAN port 

You would configure ports that are switch ports using these steps:

- create a new vlan, perhaps vlan 10 (note this is to follow the advice to not have user ports in the default vlan 1)

- choose one of the interfaces that act as switch port and configure it as an access port in vlan 10

- configure a vlan interface for vlan 10

- assign as the IP on the vlan 10 interface



Ahh...ok, that makes more sense.   The current 1921's are plugged into a access port on the core switch so they are tagged with a vlan already.  I'd just plug the ISR1111 into a trunk port  since the router would already be tagging the VLAN.  Thanks for the clarification.

My response was trying to address the question that you asked "how do I assign a LAN port" Perhaps I should have asked for more information about your environment and taken that into consideration as I made my suggestion. Am I correct in assuming that is an address in the LAN of your network? How are the routers connected to the core switch? Are they connected to access port on the core or are they connected to trunk interfaces on the core? On the core is there a single vlan/single subnet or are there multiple vlans/multiple subnets?


If the routers are connected to access ports then it will be easy to modify my suggestion - just take the vlan number of those access ports and modify my suggestions substituting that vlan number for the 10 in my suggestion. If it is a trunk connection then I need more information to be able to appropriately modify my suggestion.