Explanation

Unlike legacy network technologies such as ISDN, Frame Relay, and ATM that defined separate data and control channels, IP carries all packets within a single pipe. Thus, IP network devices such as routers and switches must be able to distinguish between data plane, control plane, and management plane packets to treat each packet appropriately.From an IP traffic plane perspective, packets may be divided into four distinct, logical groups:1. Data plane packets - End-station, user-generated packets that are always forwarded by network devices to other end-station devices. From the perspective of the network device, data plane packets always have a transit destination IP address and can be handled by normal, destination IP address-based forwarding processes.2. Control plane packets - Network device generated or received packets that are used for the creation and operation of the network itself. From the perspective of the network device, control plane packets always have a receive destination IP address and are handled by the CPU in the network device route processor. Examples include protocols such as ARP, BGP, OSPF, and other protocols that glue the network together.3. Management plane packets - Network device generated or received packets, or management station generated or received packets that are used to manage the network. From the perspective of the network device, management plane packets always have a receive destination IP address and are handled by the CPU in the network device route processor. Examples include protocols such as Telnet, Secure Shell (SSH), TFTP, SNMP, FTP, NTP, and other protocols used to manage the device and/or network.4. Services plane packets - A special case of data plane packets, services plane packets are also user-generated packets that are also forwarded by network devices to other end-station devices, but that require high-touch handling by the network device (above and beyond normal, destination IP address-based forwarding) to forward the packet. Examples of high-touch handling include such functions as GRE encapsulation, QoS, MPLS VPNs, and SSL/IPsec encryption/decryption, etc. From the perspective of the network device, services plane packets may have a transit destination IP address, or may have a receive destination IP address (for example, in the case of a VPN tunnel endpoint).

Use cu-red under interfaces facing SW1 & SW3:
On R1:
interface Ethernet0/0
ip vrf forwarding cu-red
ip address 192.168.1.254 255.255.255.0
Check reachability to SW1:
R1#ping vrf cu-red 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.2.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms On R2:
interface Ethernet0/0
ip vrf forwarding cu-red
ip address 192.168.2.254 255.255.255.0
Check reachability to SW3:
R2#ping vrf cu-red 192.168.2.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
!!!!!
Use vrf cu-green for SW2 & SW4:
On R1:
interface Ethernet0/1
ip vrf forwarding cu-green
ip address 192.168.20.254 255.255.255.0
Test reachability to SW2:
R1#ping vrf cu-green 192.168.20.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.22.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
On R2:
interface Ethernet0/1
ip vrf forwarding cu-green
ip address 192.168.22.254 255.255.255.0
Test reachability to SW4:
R2#ping vrf cu-green 192.168.22.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.20.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
On R1:
interface Ethernet0/2.100
mpls ip
!
interface Ethernet0/2.200
mpls ip
!
Configure BGP:
router bgp 65000
neighbor 10.10.10.2 remote-as 65000
neighbor 10.10.20.2 remote-as 65000
!
address-family vpnv4
neighbor 10.10.10.2 activate
neighbor 10.10.20.2 activate
exit-address-family
!
address-family ipv4 vrf cu-green
redistribute connected
exit-address-family
!
address-family ipv4 vrf cu-red
redistribute connected
exit-address-family
!
R1(config)#ip vrf cu-red
R1(config-vrf)#route-target both 65000:100
!
R1(config)#ip vrf cu-green
R1(config-vrf)#route-target both 65000:200
On R2:
interface Ethernet0/2.100
mpls ip
!
interface Ethernet0/2.200
mpls ip
!
router bgp 65000
neighbor 10.10.10.1 remote-as 65000
neighbor 10.10.20.1 remote-as 65000
!
address-family vpnv4
neighbor 10.10.10.1 activate
neighbor 10.10.20.1 activate
exit-address-family
!
address-family ipv4 vrf cu-green
redistribute connected
exit-address-family
!
address-family ipv4 vrf cu-red
redistribute connected
exit-address-family
R2(config)#ip vrf cu-red
R2(config-vrf)#route-target both 65000:100
!
R2(config)#ip vrf cu-green
R2(config-vrf)#route-target both 65000:200
Verification:
From SW1 to SW3:
SW1#ping 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
But can't Reach SW2 or SW4 in VRF cu-green:
SW1#ping 192.168.22.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.22.1, timeout is 2 seconds:
U.U.U
Success rate is 0 percent (0/5)
SW1#ping 192.168.20.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.20.1, timeout is 2 seconds:
U.U.U
Success rate is 0 percent (0/5)
Same Test for SW2:
From SW2 to SW4:
SW2#ping 192.168.20.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.20.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
But can't Reach SW3 or SW1 in VRF cu-red:
SW2#ping 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
U.U.U
Success rate is 0 percent (0/5)
SW2#ping 192.168.2.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.2.1, timeout is 2 seconds:
U.U.U
Success rate is 0 percent (0/5)
Both R1 & R2 has separate tables for VRFs cu-red and cu-green.

Explanation
OSPF type 1 route is always preferred over a type 2 route for the same destination so we can set metric-type 1 at Site-A RTR1 so that it is preferred over Site-B RTR2.
Note:
Routes are redistributed in OSPF as either type 1 (E1) routes or type 2 (E2) routes, with type 2 being the default.
- A type 1 route has a metric that is the sum of the internal OSPF cost and the external redistributed cost.
- A type 2 route has a metric equal only to the redistributed cost.
- If routes are redistributed into OSPF as type 2 then every router in the OSPF domain will see the same cost to reach the external networks.
- If routes are redistributed into OSPF as type 1, then the cost to reach the external networks could vary from router to router.