Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2ArchitectureHard
A multinational corporation is expanding its network infrastructure into several new regions, requiring segregated network environments for different business units while reusing the same IP address space in each region to simplify design and conserve addresses. The network team needs a solution that provides full routing table isolation between these environments without deploying separate physical routers or VLANs for each. Which network virtualization technology is best suited for this requirement?
- ANetwork Address Translation (NAT)
- BVLAN Trunking Protocol (VTP)
- CGeneric Routing Encapsulation (GRE) tunnels
- DVirtual Routing and Forwarding (VRF)
Show answer & explanationAnswer & explanation
Correct answer: D. Virtual Routing and Forwarding (VRF)
Virtual Routing and Forwarding (VRF) allows multiple independent routing tables to coexist on the same router, providing full routing segregation. This enables the reuse of IP address space for different business units within the same physical infrastructure, without inter-router communication between VRFs by default, perfectly meeting the stated requirements.
Why the other options are wrong
- A. Network Address Translation (NAT) maps private IP addresses to public ones but does not provide routing table isolation or allow for the reuse of the same private IP address space across segregated environments on the same router.
- B. VLAN Trunking Protocol (VTP) manages VLANs across switches but does not provide routing table isolation or IP address space reuse on a single router.
- C. GRE tunnels encapsulate traffic between two endpoints but do not provide routing table isolation on a single device or facilitate IP address reuse in the manner described.
Virtual Routing and Forwarding (VRF)
VRF is a technology that allows multiple instances of a routing table to exist within the same router at the same time. Each VRF operates independently, enabling IP address space reuse and network segregation.
- Provides full routing table isolation.
- Allows IP address space reuse.
- Each VRF acts as an independent virtual router.
- Commonly used in MPLS VPNs and campus segmentation.
Memory trick: Virtualization: VRF for routing, VLAN for switching, GRE for tunnels, NAT for addresses.