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Virtual Routing and Forwarding Table (VRF) allows to create multiple routing tables within a single router. Each of them is assigned to a customer; therefore customers can use the same IP (even private IP) with other customers without confusing the PE router.


In the above example, R0 is the Provider Edge (PE) router which is on the ISP side while R1 and R2 are customer routers (CustomerA and CustomerB respectively).

R0(config)#ip vrf CustomerA
R0(config-vrf)#rd 1:1
R0(config-vrf)#ip vrf CustomerB
R0(config-vrf)#rd 2:2

The first command “ip vrf CustomerA” enters VRF configuration mode and defines the VPN routing instance by assigning a VRF name (CustomerA).
The second command “rd 1:1” creates routing and forwarding tables. The “rd” command is in the format ASN:nn or IP-address:nn

R0(config)#interface f0/0
R0(config-if)#ip vrf forwarding CustomerA
R0(config-if)#ip address
R0(config-if)#no shutdown

R0(config)#interface f0/1
R0(config-if)#ip vrf forwarding CustomerB
R0(config-if)#ip address
R0(config-if)#no shutdown

The “ip vrf forwarding CustomerA” associates the routing and forwarding table “CustomerA” with interface f0/0.

At customer sites we don’t need to do any special configuration, just assign an IP address of each interface and “no shut” them.

R1(config)#interface f0/0
R1(config-if)#ip address
R1(config-if)#no shutdown

R2(config)#interface f0/0
R2(config-if)#ip address
R2(config-if)#no shutdown

R0 router recognizes each customer IP by the “Customer name” (CustomerA or CustomerB)


Notice that the pings are still successful when two customers use the same IP address.

R1 and R2 can ping to PE router with the same IP



We can also see what is inside R0’s VRF table with the “show ip vrf” command


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