Carrier's Carrier - HP 10500 Series Configuration Manual

Figure 34 Network diagram for inter-AS option C
VPN 1
CE 1
PE 1
MPLS backbone
AS 100
CE 2
VPN 2
To improve the scalability, you can specify an RR in each AS to maintain all VPN-IPv4 routes and to
exchange VPN-IPv4 routes with PEs in the AS. The RRs in two ASs establish an inter-AS VPNv4
connection to advertise VPN-IPv4 routes, as shown in
Figure 35 Network diagram for inter-AS option C using RRs

Carrier's carrier

If a customer of the MPLS L3VPN service provider is also a service provider, 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 learn the routes of the customer network connected to
a Level 2 carrier. It only learns the routes for delivering packets between different sites of the Level 2
carrier. Routes of the customer networks connected to a Level 2 carrier are exchanged through the BGP
Multi-hop MP-EBGP
ASBR 1
EBGP
(PE)
PE 2
Multi-hop MP-EBGP
VPN LSP
LSP
VPN 1
PE 3
ASBR 2
(PE)
MPLS backbone
AS 200
PE 4
VPN 2
Figure 35.
96
CE 3
CE 4