NM-16ESW and a HWIC-9ESW in the same 2811 why doesn't it work?

Unanswered Question

I have a 2811 router and no space for equipment. I put a NM-16ESW switch module in it and it worked great. Later I needed POE for a number of devices, so I installed an HWIC-D-9ESW-POE card with a new power supply. Now I can connect on any device on the HWIC but not the NM-16ESW.

It's all the same VLAN, but I can't even ping the VLAN interface from a device connect to the NM-16ESW. Plug it into the HWIC and the device can ping up a storm.

Any ideas?

I have this problem too.
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glen.grant Thu, 02/22/2007 - 17:24

Did you connect the 2 switches together with a external cat 5 cable , you must tie them together if you want them as a single switch.

Configuring Intrachassis Stacking

Perform this task to extend Layer 2 switching in the router by connecting the Gigabit Ethernet ports of the EtherSwitch network module.


1. enable

2. configure terminal

3. interface gigabitethernet slot/port

4. switchport stacking-partner interface gigabit slot/port

5. exit


Command or Action


Step 1



Router> enable

Enables privileged EXEC mode.

?Enter your password if prompted.

Step 2

configure terminal


Router# configure terminal

Enters global configuration mode.

Step 3

interface gigabitethernet slot/port


Router(config)# interface gigabitethernet 2/0

Selects the Gigabit Ethernet interface to configure.

Step 4

switchport stacking-partner interface gigabitethernet slot/port


Router(config-if)# switchport stacking-link interface gigabitethernet 3/0

Creates the intrachassis stacking between the current Gigabit Ethernet (GE) interface and the stacking link partner GE interface.

?In this example, GE interface 2/0 is stacked on GE interface 3/0 to form an extended VLAN within one chassis on the router.

Step 5



Router(config-if)# exit

Exits interface configuration mode and returns the router to global configuration mode.

?Repeat this command to exit global configuration mode and return to privileged EXEC mode.

sachinraja Thu, 02/22/2007 - 17:28

Agree with Glen.. this is the best way of doing this ....

Thanks for the info glen..


sachinraja Thu, 02/22/2007 - 17:25

Hello murphy,

are u not able to ping between the end stations connected on these cards ?? is the local communication within the modules working ?? You basically need to give a layer 3 vlan IP address for you to enable access between the cards.. this is a router module and hence the router has to know how to forward the packets to the end stations..

do let us know in detail..


mihanlin Mon, 02/26/2007 - 19:16


Unfortunately you need a gig uplink port on each of the cards for it to work.

The following FAQ describes it in detail:


"An intrachassis stack requires a Gigabit Ethernet interface on each module. You must connect the modules externally with the Gigabit Ethernet interfaces and a crossover cable."

The 16-port EtherSwitch NM can accept a single-port Gigabit Ethernet daughtercard.

Hope this helps.


Cisco TAC - LAN Switching


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