For a Carrier Supporting Carrier (CSC) VPRN where the customer carrier is a BGP/MPLS VPN Service Provider (SP), which of the following is FALSE?

The question's premise explicitly states that the customer carrier is a "BGP/MPLS VPN Service Provider". By definition, such a provider utilizes an MPLS-enabled core to establish Label Switched Paths (LSPs) for traffic transport and uses Multiprotocol BGP (MP-BGP) to exchange VPN routing information. This architecture is fundamentally different from a "pure IP network," which would rely solely on IP routing protocols like OSPF or IS-IS for reachability without an underlying MPLS transport for VPN services. Therefore, the statement that a BGP/MPLS VPN SP "can be a pure IP network" is a direct contradiction of the established premise, making it the false statement.

B. A customer carrier, as a service provider, is expected to offer a diverse portfolio of services, including both Layer 2 and Layer 3 VPNs, to its end-customers.

C. In the CSC model, the backbone provider configures a single VPRN instance to interconnect all of the customer carrier's sites, treating the entire customer network as one VPN customer.

D. This is the specific terminology for this model. When a VPRN service is used to transport another VPRN service, the architecture is defined as a hierarchical VPRN.

1. Nokia 7750 SR OS MPLS Guide, Release 22.10.R1, "Carrier-of-Carriers VPRN" section. This document describes the CSC architecture. It states, "If the customer carrier is an ISP or a VPRN service provider, the VPRN service is a hierarchical or recursive VPRN service." This confirms that a VPRN service provider (the customer carrier) uses the backbone VPRN, and this model is called hierarchical VPRN (validating option D). The guide also implicitly confirms that a BGP/MPLS VPN provider is not a pure IP network by detailing the MPLS-based mechanisms involved.

2. Nokia 4A0-106 Courseware, "Module 4: Virtual Private Routed Network (VPRN) services". The course material on Hierarchical VPRNs (Carrier-of-Carriers) explains that the backbone provider creates a single VPRN to provide connectivity for the customer carrier. The customer carrier then runs its own services, which can be L2 or L3, over this transport VPRN (validating options B and C).

3. RFC 4364, "BGP/MPLS IP Virtual Private Networks (VPNs)", Section 1. This foundational document defines a BGP/MPLS VPN provider as one that uses "IP/MPLS" backbones to provide services. This inherently means it is not a "pure IP network" (invalidating option A).