243
Configuring nested VPN
Network requirements
The service provider provides nested VPN services for users, as shown in
.
•
PE 1 and PE 2 are PE devices on the service provider backbone. Both of them support the nested
VPN feature.
•
CE 1 and CE 2 are connected to the service provider backbone. Both of them support VPNv4
routes.
•
PE 3 and PE 4 are PE devices of the customer VPN. Both of them support MPLS L3VPN.
•
CE 3 through CE 6 are CE devices of the sub-VPNs for the customer VPN.
The key of nested VPN configuration is to understand the processing of routes of sub-VPNs on the service
provider PEs:
•
When receiving a VPNv4 route from a CE (CE 1 or CE 2 in this example), a service provider PE
a.
Replaces the RD of the VPNv4 route with the RD of the MPLS VPN on the service provider
network where the CE resides.
b.
Adds the export target attribute of the MPLS VPN on the service provider network to the
extended community attribute list.
c.
Forwards the VPNv4 route.
•
To implement exchange of sub-VPN routes between customer PEs and service provider PEs,
MP-EBGP peers must be established between service provider PEs and customer CEs.
Figure 68
Network diagram
Table 18
Interface and IP address assignment
Device Interface IP
address
Device
Interface
IP address
CE 1
Loop0
2.2.2.9/32
CE 2
Loop0
5.5.5.9/32
Vlan-int2
10.1.1.2/24
Vlan-int1
21.1.1.2/24
Vlan-int1
11.1.1.1/24
Vlan-int2
20.1.1.1/24
