I have run into an interesting issue setting the native VLAN between one of my Cisco Catalyst 2960 and my Layer 3 switch (third party). Here is the setup, the layer three switch is set up to run on native vlan 171 and allows vlans 1,2,151,170-175,1000-1001 over the trunk. The Cisco switch in question is configured to trunk native vlan 1 and allow 1,2,151,170-175,1000-1001. The layer 3 supports RSTP and its bridge ID was set lower than the Cisco switches downstream so it would always be root.
So from what I have describe I obviously have a native vlan mismatch over this trunk. Downstream of this specific Cisco switch has 4 other switches connected to it which trunk native vlan 1001 and allow vlans 1,2,151,170-175,1000-1001.
So everytime I attempt to correct the native vlan mismatch between the Layer 3 switch and the one Cisco Switch the trunk will not pass any traffic over that trunk. The Layer 3 switch sees there is something plugged in and sends ARPS but no replies come back. The changes being attempted are as to set the native vlan to 1001 on both ends of the trunk. The only way i can have the same native vlan is if i set it to vlan 1 on both ends. Support for the third party Layer 3 switch say's there are no error's or issues on that end. Does anyone have any ideas? do I have an spann tree issue?
The layer 3 switch is not becoming the root for all the VLANs, just for VLAN 1, another access switch is the root for the rest of the VLANs. I have not been able to duplicate this in a Lab which makes it more confusing.