In VRF-Lite, Route distinguisher (RD) identifies the customer routing table and "allows customers to be assigned overlapping addresses". The below example shows overlapping IP addresses configured on two interfaces which belong to two different VPNs: Router(config)#ip vrf VRF_BLUE Router(config-vrf)# rd 100:1 Router(config-vrf)# exit Router(config)#ip vrf VRF_GREEN Router(config-vrf)# rd 100:2 Router(config-vrf)# exit Router(config)# interface GigabitEthernet0/1 Router(config-if)# ip vrf forwarding VRF_BLUE Router(config-if)# ip address 10.0.0.1 255.0.0.0 Router(config-vrf)# exit Router(config)# interface GigabitEthernet0/2 Router(config-if)# ip vrf forwarding VRF_GREEN Router(config-if)# ip address 10.0.0.1 255.0.0.0 In this example, the RD will be added to the beginning of the IP address. For example with VRF_BLUE (rd 100:1), an IP address will be seen like this: 100:1:10.0.0.1/8 so that it is unique in the routing table.