Cisco Certified Internetwork Expert (CCIE) Practice Test

Which two statements about NVGRE are true?

1. It allows a virtual machine to retain its MAC and IP addresses when it is moved to different hypervisor on a different L3 network

2. The virtual machines reside on a single virtual network regardless of their physical location

3. NVGRE endpoints can reside within a virtual machine

4. It supports up to 32 million virtual segments per instance

The correct answer is: The virtual machines reside on a single virtual network regardless of their physical location

The statement that virtual machines reside on a single virtual network regardless of their physical location is accurate because NVGRE (Network Virtualization using Generic Routing Encapsulation) is designed to encapsulate Layer 2 Ethernet frames within Layer 3 packets. This allows for the creation of a virtualized overlay network that abstracts the underlying physical network architecture. With NVGRE, VMs can communicate as if they are on the same local network, even if they are distributed across different data centers or locations, thus enabling seamless mobility and connectivity. This characteristic is a significant advantage in environments that utilize virtualization because it provides flexibility in VM placement and workload balancing without requiring changes to the addressing or physical networking configurations. As a result, NVGRE facilitates multi-tenant environments, cloud services, and enhances the overall scalability of network virtualization. Understanding the nature of NVGRE helps clarify why other statements might not align with its capabilities. For instance, while NVGRE does enable flexibility in VM mobility, the retention of MAC and IP addresses across different L3 networks is a more complex process dependent on specific configurations and might not be inherently guaranteed by NVGRE alone. Additionally, while endpoints can exist within a virtual machine, the focus of NVGRE is primarily on facilitating network connectivity between these VMs rather than