338Destination/Mask Proto Pre Cost NextHop Interface3.3.3.3/32 Direct 0 0 127.0.0.1 InLoop05.5.5.5/32 BGP 255 0 2.2.2.9 NULL020.1.1.0/24 OSPF 10 1563 100.1.1.1 Vlan11100.1.1.0/24 Direct 0 0 100.1.1.2 Vlan11100.1.1.2/32 Direct 0 0 127.0.0.1 InLoop0120.1.1.0/24 BGP 255 0 2.2.2.9 NULL0Issue the display ip routing-table command on the CEs, and you can see that the cost of the OSPFroute to the peer CE is now 10 (the cost configured for the sham link), and that the next hop is nowthe VLAN interface 11 connected to the PE. This means that VPN traffic to the peer will beforwarded over the backbone. Take CE 1 as an example:[CE1] display ip routing-tableRouting Tables: PublicDestinations : 9 Routes : 9Destination/Mask Proto Pre Cost NextHop Interface20.1.1.0/24 Direct 0 0 20.1.1.1 Vlan1320.1.1.1/32 Direct 0 0 127.0.0.1 InLoop020.1.1.2/32 Direct 0 0 20.1.1.2 Vlan1330.1.1.0/24 OSPF 10 1574 100.1.1.2 Vlan11100.1.1.0/24 Direct 0 0 100.1.1.1 Vlan11100.1.1.1/32 Direct 0 0 127.0.0.1 InLoop0120.1.1.0/24 OSPF 10 12 100.1.1.2 Vlan11127.0.0.0/8 Direct 0 0 127.0.0.1 InLoop0127.0.0.1/32 Direct 0 0 127.0.0.1 InLoop0Issue the display ospf sham-link command on the PEs. The output shows that a sham link has beenestablished. Take PE 1 as an example:[PE1] display ospf sham-linkOSPF Process 100 with Router ID 100.1.1.2Sham Link:Area NeighborId Source-IP Destination-IP State Cost0.0.0.1 120.1.1.2 3.3.3.3 5.5.5.5 P-2-P 10Issue the display ospf sham-link area command. The output shows that the peer state is Full:[PE1] display ospf sham-link area 1OSPF Process 100 with Router ID 100.1.1.2Sham-Link: 3.3.3.3 --> 5.5.5.5Neighbor ID: 120.1.1.2 State: FullArea: 0.0.0.1Cost: 10 State: P-2-P Type: ShamTimers: Hello 10, Dead 40, Retransmit 5, Transmit Delay 1Configuring BGP AS number substitutionNetwork requirementsAs shown in Figure 86, CE 1 and CE 2 belong to VPN 1 and are connected to PE 1 and PE 2 respectively.In addition, they use the same AS number 600.