3com S7906E Manuel De Montage

 

1-12 

Figure 1-9 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 1-10 Network diagram for inter-provider VPN option C using RRs 

 

 

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. 

For good scalability, the Level 1 carrier does not inject the external routes of a Level 2 carrier; it only 

injects routes for switching packets from different sites of the Level 2 carrier. The external routes 

maintained by a Level 2 carrier are exchanged through BGP sessions established between related