Hi,
Can't say I've see this before, and my take on this configuration is these two vlan 50 instantiations on the same 2811 router don't step on each other's layer3 address because one is routed and the other is switched. Anyone disagree?
vlan 50
name WorkStations
interface FastEthernet0/0
no ip address
ip flow ingress
duplex full
speed 100
interface FastEthernet0/0.50
encapsulation dot1Q 50
ip address 12.x.y.z 255.255.255.252
no cdp enable
.
.
.
interface FastEthernet1/10
switchport access vlan 50
spanning-tree portfast
interface Vlan50
ip address 10.105.50.1 255.255.255.0