Intervlan between a Superstack II 3300 switch and a Cisco 6509 1

[joysa]

I have multiple secondary subnets configured in the 3com 3300 and I need to create subinterfaces in the 6509 to assign them a physical IP address. A DHCP server is configured to assign IP addresses for each VLAN. I'm using a 6509 running Native IOS. I created vlans in the 3300, one per secondary subnet, and added ports to them (tagged as 802.1q). I configured port 26 for trunking and member of Vlan1. In the 6509 I configured port 4/24 as a trunk with 802.1q tag and member of Vlan1. I made all my vlans members of the trunk (at the 6509 end). Using interface Vlan # command, I assigned IP addresses to the VLANS. Also I configured the IP helper in each subinterface in order to broadcast the DHCP packets to the DHCP server. This configuration is not working. I can't ping between w/s in the same vlans. What I'm doing wrong. Can you interconnect VLANS between 3com and Cisco switches.


Thanks

 

[jacob200]

Did you ever solve this? Perhaps I could look at your configs. You know that dhcp doesn't work with secondary addresses, right? I'd like to get feedback from you regarding the Native IOS.

 

[TreyJ]

I'm currently trying to get trunking to work between a 3COM 4400 and a Cisco Catalyst 4000. I'm not sure whether Vlan 1 has to be tagged or untagged on the 3COM device.

 

[krr]

On a Cisco VLAN trunk, all VLANs are tagged except(!) the native VLAN (usually VLAN 1), which goes untagged.

On the 3Com side, the port connected to the Cisco trunk must be member of VLAN 1 (untagged) and 802.1Q tagged for all other VLANs. The rest of the ports have to be untagged members of their VLAN. Do NOT define them as 802.1Q, because this will send tagged frames out on the port and you won't be able to reach anything.

Yes, IEEE 802.1Q is a standard, but the philosophy of the implementation differs a lot between vendors. And they use different words for the same thing. Cisco has the plus of making VLANs very easy within their product range. They try to hide much of the complexity. With 3Com (and others) you have to really understand what you are doing.

Cheers *Rob

 

[AlexxIT]

Hi all,

Yes i agree with KRR.

Remember that 3Com Vlan1 is not the same as Cisco Vlan1.
I have tryed it with a Cisco 4006 and 3Com 3300
You must not tag the trunk port on the 3Com all other vlans yo can tag.
And to correct Krr Cisco vlan1 is always standard TAG'd if it is a trunk.

Have fun
Alex

 

[TreyJ]

Thanks for the assist (even though I didn't start this thread!). I'm still having problems, but it is a Cisco Catalyst 4006 issue, not 3COM.