If you used Native IOS...set the sw1Router(config-if)# switchport trunk native vlan vlan_ID (Optional) Configures the 802.1Q native VLAN. When configuring the native VLAN, note the following: The vlan_ID can be 1 through 4094, except reserved VLANs ...
this problem occured between sw1 and sw2 vlan mismatch...I think change sw2 vlan number and vlan name, sw2 vlan 1 --> vlan 66sw1 and sw2 connect same vlan.switch is not recommand used default vlan (vlan 1) for end nodevlan 1 is only used for manag...