802.1Q Trunk on a 2950 switch problem

runner_836 · ‎07-31-2008

I have a 2950 switch f0/24 set up as a trunking port. I have made vlan 100 the native vlan and have 10,20,30 as other vlans also vlan 1 as default. I'm connected to a non-cisco switch. I'm only able to ping when I enable redundancy (ie rstp) on the non-cisco switch. Is there something that I need to change in the 2950 to communicate with non-cisco switch without redundancy (ie pvst or spanning-tree forwarding)? I notice that vlan 1 is included in the vlan management, vlan access, but not the spanning-tree forwarding, is this normal? any ideas would be appreciated.

sbilgi · ‎08-06-2008

Verify that the trunking mode and encapsulation are configured correctly. Make certain that the native VLAN is the same on all of the 802.1q trunks that connect the Cisco switches to the non-Cisco 802.1q cloud.

If multiple Cisco switches are connected to a non-Cisco 802.1q cloud, all of the connections must be through 802.1q trunks. Do not connect Cisco switches to a non-Cisco 802.1q cloud through ISL trunks or through access ports. If this is done, it causes the switch to place the ISL trunk port or access port into the spanning tree port inconsistent state and no traffic passes through the port.

http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a008017f86a.shtml