Cisco Support Community
Community Member

Cisco 2811 and NM-16ESW

For some reason I cannot seem to get a connection between the router and the switch. I see the FE ports on the siwtch, sh ver includes all 18 FE ports, but it seems that there is no backplane connection. The only way I can get conenctivity to the switch module is to jumper between one of the routers FE ports and a NM port. The switch will not accept any IP addressing on the same network as the router becasue of overlap. Am I just being stupid? My understanding was this NM would have a backplane connection to the router. Some docs mention a GE conneection that should show up and there were two parts to the config, one to set up the interconnect and then to set up the switch.

IOS was chosen by software advisor for compatibility.


Re: Cisco 2811 and NM-16ESW

You need to create some virtual VLAN interfaces on your router, and these will automatically connect into the VLANs you are using one the switch. If the switch is at its default setting, then you will only need a virtual interface for VLAN 1.

interface vlan 1

ip address


Kevin Dorrell


Community Member

Re: Cisco 2811 and NM-16ESW

I had tried that but it didn't seem to function correctly. These assemblies will be used in small branch offices terminating VPN tunnels.I originally set it up without the NM and everything was fine, but when I added the NM-16ESW, I couldn't add an IP address of the same subnet to VLAN 1 that was assingned to my LAN (inside) router interface.

I moved the IP of the inside interface to the VLAN, which took, but I had difficulty with the VPN tunnel. I assume that by adding an IP address to the VLAN it was considered a routed (L3) interface and that is why I got the overlapping subnet error.

Does the NM integrate its interfaces into the routers interfaces or are they considered interaces on a separate device? It would make sense to me that there would be an internal connection to the NM and that I would assign an IP address to the vlan and the NM would function as a L2 device as if it were a separate switch, but with an internal connection.

I also tried creating a new vlan an assigning it an IP address, but again I got the overlapping subnet error.

Does the NM need to be boostrapped into the router. I have not found a way to connect to the NM directly. I tried following but it seems to me that I am missing an important part of the process to install the NM into the router, since I cannot see it in the way it is described in this doc.

Community Member

Cisco 2811 and NM-16ESW

Searching through archives for this exact problem/situation. Did you figure this out? Request information on what you did to fix this, if at all.



Re: Cisco 2811 and NM-16ESW


Long time no see..!!

CreatePlease to create content