White Paper: Data Center Interconnect Design Options and Implementation Guide


This document explains Apstra’s implementation of Data Center Interconnect (DCI) with EVPN, which allows an end user to connect two data centers using AOS to manage one or many IP fabric egress points.

Why Data Center Interconnect

Historically, enterprises have leveraged Data Center Interconnect (DCI) technology as a building block for business continuity, disaster recovery (DR), or Continuity of Operations (COOP). These service availability use cases primarily relied on the need to connect geographically separated data centers with Layer-2 connectivity for application availability and performance. With the rise of highly virtualized Software-Defined Data Centers (SDDC), cloud computing, and more recently, edge computing, additional use cases have emerged:

    • Colocation Expansion: Share compute and storage resources to colocation data center facilities.
    • Resource Pooling: Share and shift applications between data centers to increase efficiency or improved end-user experience.
    • Rapid Scalability: Expand capacity from a resource-limited location to another facility or data center
    • Legacy Migration: Gracefully move applications and data off older and inefficient equipment and architecture to more efficient, higher-performing, and cost-effective architecture.


There are several different technologies available to customers that address DCI. On one end of the spectrum is the combination of Multi-Protocol Label Switching (MPLS) with Virtual Private LAN Service (VPLS). While this approach is standards-based and has extensive software and hardware options, it is neither simple to operate and troubleshoot nor inexpensive as specialized hardware and software are required. At the other end of the spectrum, customers will find vendor proprietary solutions like Cisco OTV, but this also has shortcomings. While somewhat easier to configure initially, it isn’t substantially easier to operate or troubleshoot and requires expensive licenses coupled with specialized hardware and software. Additionally, and perhaps most importantly, being highly proprietary restricts customers to a single vendor. This compromises customers’ pricing negotiations and adds tremendous challenges when migrating to new architectures, vendors, or even merger and acquisition events where vendor diversity is almost guaranteed. There is now a widely tested and substantially better option. Customers can use Apstra AOS to deploy and manage a vendor inclusive DCI solution that is simple, flexible, and Intent-Based. AOS utilizes the standards-based MP-BGP EVPN with VXLAN, which has achieved broad software and hardware adoption in the networking industry. Customers can choose from a vast selection of cost-effective commodity hardware from traditional vendors to white-box ODMs and software options ranging from conventional vendor integrated Network Operating Systems (NOS) to disaggregated open source options.