mstp vrrp经典案例LSW3sys sys LSW3VLAN10int e003p l a p de vlan10int e001p l t p t al vlan all int e002p l t p t al vlan all LSW4sys sys LSW4VLAN20int e003p l a p de vlan20int e001p l t p t al vlan all int e002p l t p t al vlan all LSW1sys sys LS VLANb1020int g003p l t p t al vlan all int g001p l t p t a