What are the available options to interconnect private Datacenters? (Select 2)

Data Center Interconnect (DCI) refers to the technology used to connect two or more geographically distinct data centers. A Virtual Private Network (VPN), such as an IPsec or MPLS VPN, creates a secure, logical network over a shared or public infrastructure like the internet, providing a common method for DCI. A private backbone is a dedicated, high-capacity network (e.g., using dark fiber or DWDM) built or leased by an organization. It offers high performance, security, and reliability, making it a primary option for interconnecting critical data center sites.

C. VLAN: A Virtual LAN (VLAN) is a Layer 2 construct used to segment a single physical network into multiple logical broadcast domains. It operates within a network, not between geographically separate data centers.
D. VIP: A Virtual IP (VIP) address is a logical address used for service high-availability and load balancing. It does not provide the underlying network connectivity required to interconnect data centers.

1. Nokia White Paper: "Modernize your data center interconnect". This document discusses the evolution of DCI technologies. On page 4, it explicitly states, "DCI has traditionally been provided by Layer 2/3 VPN services over an IP/MPLS backbone or by private line services over an optical transport network." This confirms both VPNs and private backbones as primary DCI options.

2. Nokia Application Note: "Nokia Data Center Fabric Solution Guide". In the section "Multi-site data center and interconnect," this guide details solutions for connecting data centers over various WAN technologies, including IP VPN and optical transport networks (which constitute a backbone). (Reference specific to Nokia's DCI portfolio).

3. Kurose, J. F., & Ross, K. W. (2021). Computer Networking: A Top-Down Approach (8th ed.). Pearson. This standard university textbook describes the core concepts. Chapter 8.7, "Securing TCP Connections: SSL," and the broader discussion on IPsec explain the principles of VPNs for connecting private networks. Chapter 1.3, "The Network Core," describes the concept of a network backbone used for long-haul data transmission between interconnected routers, which is the foundation for a private backbone DCI.