Unable to create sub interfaces in C1109-4PLTE2P

[ba097e]

When I try to create a sub interface on a GigabitEthernet interface I receive the following error message.

ccsEdge2(config)#interface GigabitEthernet 0/1/2.111
^
% Invalid input detected at '^' marker.

What is the issue here.

[MHM Cisco World]

Try do 

No switch port 

Then config subinterface 

MHM

[ba097e]

That’s not an issue since the router's interfaces are not configured as Switchports. Could the issue that I'm having be due to the router using the encapsulation ARPA?

[MHM Cisco World]

Friend it not config it by defualt switchport

So we need first to change it to l3 port then config subinterface 

MHM

[ba097e]

Okay what are the commands to do that?

[MHM Cisco World]

The command is 

No switchport <<-this must add under main interface 0/1/2

Also check @Joseph W. Doherty

He is right some device it have one Wan interfere and many other l2 Ethernet interfere and these l2 Ethernet can not config as router port

So if 

No switchport 

Command not accept you Need to add vlan and config vlan SVI

MHM

[Giuseppe Larosa]

Hello @ba097e ,

@MHM Cisco World is right the port you would like to configure is by default a switchport

see config guide below

https://www.cisco.com/c/en/us/td/docs/routers/access/1100/software/configuration/xe-16-7/cisco_1100_series_swcfg_xe_16_7_x/cisco_1100_series_swcfg_chapter_01000.html#concept_ydz_v1m_1z

you should try to use no switchport under the main interface before attempting to create subinterfaces.

As an alternative you can create multiple SVI VLAN interfaces and you configure the L2 port as an 802.1Q trunk that allows the corresponding VLANs  to have a functional equivalent of a router on a stick.

Hope to help

Giuseppe

[ba097e]

BTW these are brand new routers. I tried to use the command no switchport but the router replied Incomplete command.

[Giuseppe Larosa]

Hello @ba097e ,

if these ports gi0/1/x are only L2 ports you cannot define subinterfaces and you need to use the port as an 802.1Q trunk allowing the desired set of VLANs like 10.20,30 and so on. Then you configure the corresponding SVI interfaces for VLANs 10,20,30 and this is functionally equivalent to the use of subinterfaces.

WAN ports are router ports and they likely support subinterfaces , the LAN ports gi0/1/x are likely only L2 ports.

Hope to help

Giuseppe

[Joseph W. Doherty]

I believe that may be one of the switch's "LAN" ports, i.e. L2 only (at the port level - i.e. incapable of L3).

As a couple of other replies have noted, for such port, you should be able to assign such a port, or ports, to a VLAN and define a SVI.  (Not as an alternative, though, as you might do on a L3 switch port.  I.e. it's the only way to have an associated L3 IP.)  If you define a unique SVI/VLAN per port, you almost have the equivalent of a L3 routed port.

If you want a subinterfaces equivalent, you may be able to define one of these ports as a trunk, and have multiple SVIs.

BTW, there are often other limitations to what might be done on the LAN ports.

The switch's "WAN" port should support most, if not all, router port features.  On that port, I would expect you could define subinterfaces.