Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2VirtualizationHard
A multinational corporation is expanding its network infrastructure globally and needs to establish secure, isolated communication channels between its various regional offices over a shared public network. Each regional office requires its own dedicated routing and forwarding policies, and the solution must be highly scalable to accommodate future growth. Which network virtualization technology is best suited for this large-scale, multi-site Layer 3 VPN requirement?
- AMPLS Layer 3 VPNs
- BGRE over IPsec
- CDMVPN
- DVRF-Lite
Show answer & explanationAnswer & explanation
Correct answer: A. MPLS Layer 3 VPNs
MPLS Layer 3 VPNs are the industry-standard solution for large-scale, multi-site Layer 3 VPNs, especially in service provider environments. They provide strong isolation between customer networks, support overlapping IP addresses, and are highly scalable due to the efficient label-swapping mechanism. Each customer's VPN uses a dedicated VRF instance at the provider edge (PE) router, ensuring separate routing and forwarding policies.
Why the other options are wrong
- B. GRE over IPsec provides secure tunnels but is less scalable for complex, multi-site VPNs with dedicated routing policies than MPLS VPNs.
- C. DMVPN (Dynamic Multipoint VPN) is a scalable VPN solution for spoke-to-spoke connectivity but typically for a single organization, not for multi-tenant, dedicated routing policy scenarios managed by a service provider.
- D. VRF-Lite provides Layer 3 isolation on a single router and is not a solution for connecting multiple sites over a shared public network in a scalable, service-provider fashion.
MPLS Layer 3 VPNs
A highly scalable and secure network virtualization technology that creates isolated Layer 3 VPNs over a shared MPLS backbone, commonly used by service providers.
- Uses VRFs at provider edge (PE) routers for customer isolation.
- Enables overlapping IP address spaces between different customers.
- Provides traffic forwarding based on labels, improving scalability and performance.
Memory trick: MPLS L3 VPNs: Massive Private Links, Securely.