334
Configuring BGP AS number substitution and SoO
Network requirements
CE 1, CE 2, and CE 3 belong to VPN 1 and connect to PE1, PE 2, and PE 3 respectively. CE 1 and CE
2 reside in the same site. CE1, CE2, and CE 3 all use AS number 600.
To avoid route loss, configure BGP AS number substitution on PEs. To avoid routing loops, configure a
routing policy on PE1 and PE2 respectively to add the SoO attribute to routes received from CE 1 and CE
2.
Figure 79
Network diagram
Device Interface IP
address
Device
Interface
IP address
CE 1
Loop0
100.1.1.1/32
CE 3
Loop0
200.1.1.1/32
Vlan-int2
10.1.1.1/24
Vlan-int7
10.3.1.1/24
CE 2
Vlan-int2
10.2.1.1/24
PE 2
Loop0
2.2.2.9/32
PE 1
Loop0
1.1.1.9/32
Vlan-int2
10.2.1.2/24
Vlan-int2
10.1.1.2/24
Vlan-int4
20.1.1.2/24
Vlan-int3
30.1.1.1/24
Vlan-int5
40.1.1.1/24
Vlan-int4
20.1.1.1/24
P Loop0
3.3.3.9/32
PE 3
Loop0
4.4.4.9/32
Vlan-int3
30.1.1.2/24
Vlan-int6
50.1.1.2/24
Vlan-int5
40.1.1.2/24
Vlan-int7 10.3.1.2/24
Vlan-int6 50.1.1.1/24
Configuration procedure
1.
Configure basic MPLS L3VPN. (Details not shown)
{
Configure OSPF on the MPLS backbone to allow the PEs and P device to learn the routes of the
loopback interfaces from each other.
{
Configure basic MPLS and MPLS LDP on the MPLS backbone to establish LDP LSPs.
{
Establish MP-iBGP peer relationships between the PEs to advertise VPN IPv4 routes.
{
Configure VPN 1 on PE 1 to allow CE 1 to access the network.
{
Configure VPN 1 on PE 2 to allow CE 2 to access the network.