H3C Technologies H3C S7500E Series Switches - Manual (Page 237)

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Figure 6-9 Network diagram for inter-provider VPN option C
To improve the scalability, you can specify an RR in each AS, making it maintain all VPN-IPv4 routes
and exchange VPN-IPv4 routes with PEs in the AS. The RRs in two ASs establish an inter-provider
VPNv4 connection to advertise VPN-IPv4 routes, as shown in
Figure 6-10 .
Figure 6-10 Network diagram for inter-provider VPN option C using RRs
Carrier’s Carrier
Introduction to carrier's carrier
It is possible that a customer of the MPLS L3VPN service provider is also a service provider. In this
case, the MPLS L3VPN service provider is called the provider carrier or the Level 1 carrier, while the
customer is called the customer carrier or the Level 2 carrier. This networking model is referred to as
carrier’s carrier. In this model, the Level 2 service provider serves as a CE of the Level 1 service
provider.