Two HWIC-4ESW cards - can they work together in the same vlan?

[Difan Zhao]

I can't believe that I can't get this working...

So my 3825 router has two HWIC-4ESW cards. Can they share the VLANs? PC on one card can't ping PC on the other card. Only PC on the card in slot 0 can ping the SVI interface. Is this expected behavior?

If so, if there a way to tell the routers that some vlans only belong to certain card?

Thanks,

Difan

[Peter Paluch · Accepted solution]

Hi Difan,

When using two HWIC-4ESW in a single router, you have to connect them together using their own ports and a cross-over cable, and in addition, configure both interconnected ports as so-called stacking partners. Assuming you have interconnected ports Fa0/1/0 and Fa0/2/0, then the configuration would be:

interface FastEthernet0/1/0
 switchport stacking-partner interface FastEthernet0/2/0
 no shutdown
!
interface FastEthernet0/2/0
 no shutdown

As strange as it sounds, these cards are unable to communicate together through their internal connection within the router.

Also see

http://www.cisco.com/en/US/docs/ios/12_4/lan_switch/configuration/guide/cfg_hesw.html#wp1049119

Best regards,
Peter

[Difan Zhao]

Thanks Peter!

It is also worth noted that the line protocol will be down on the stacking interface.. Interesting!

[Masoud Pourshabanian]

Hello,

As Peter said, you need the stack them. These modules are able to communicate through layer2 internally. Parent device does not provide layer 2 connectivity for different device. And also for l3 communication, they are dependent to the parent device. How about PCs in different VLAN? Can they see each other by SVI if they are in different VLANs?

[Difan Zhao]

Hi Masoud, thanks for your response. I tried with your scenario with routing part tested. I think that the VLANs and SVIs only belong to the first card. No matter on with VLAN, the PC on the second card can't ping the SVI interfaces without the stacking setup. The PC on the first card can always ping the SVI interfaces

[Masoud Pourshabanian]

It sounds really wired with Cisco devices.