Interconnection Types and Definitions: A Comprehensive Guide by DataBank

In the first article in our series on interconnections, we introduced the concept of interconnection in colocation data centers. We described the important role they play, not only in helping companies conduct vital “business as usual” operations each day, but also in making them more agile, responsive, and competitive.

Yet, we realize the term interconnection is used by vendors and other parties to describe many different approaches or technologies related to connectivity in the data center.

Therefore, this article will define interconnection, but also take a closer look at five different interconnect approaches in use today. We’ll define each one, describe how it works, and even provide some real-world examples to help bring them to life. Hopefully, we’ll establish a level of baseline clarity that will help you pick the right interconnect strategy for your business.

What is Interconnection?

To start, interconnection is an over-arching term that refers to many different physical and virtual connections companies can select to exchange data, provide business continuity and customer services, and address specific business objectives.

As a business offering itself, interconnection has come a long way since the first telecommunication providers connected networks to improve the way they exchanged voice traffic. Today, virtually every business needs to connect with others – in some way or another – to exchange data to support vital business processes.

While there are many different mechanisms for interconnection, each complete with additional variations, there are several types of interconnection services available in most data centers today. Let’s take a closer look at a few examples.

Cross-Connects

Cross-connects represent the most basic type of interconnection and generally refer to the direct, physical, and dedicated connection between two networks. Think of the familiar example of running fiber between two endpoints in a colocation data center, and you can picture how cross-connects work.

Cross-connects provide dedicated, point-to-point connectivity as well as the most reliable, efficient, and secure way to connect networks and infrastructure. They also deliver excellent reliability and low latency, great benefits for virtually any data center customer.

Internet Exchanges

An internet exchange, also known as an internet exchange point (IXP), is a switch. Companies can connect their network to an IXP using a physical cross-connect, and once they’ve established that connection, they can connect to other members of the internet exchange, without the need to run separate cables.

Companies use internet exchanges to establish peering with other networks connected to the IXP, leveraging the BGP protocol to establish peering sessions over a single physical connection, and again, without the need for new cabling. Peering is a valuable advantage for interconnected companies such as internet service providers, content delivery networks, and other service providers, as well as the enterprise, and enables them to reduce transit costs, increase capacity, and improve network performance.

Private peering is a variation that takes place in a colocation facility where two parties maintain separate network routers but connect them with a direct cable instead of connecting to the IXP. This is a beneficial use case when networks are exchanging a large volume of traffic, which won’t fit on a shared connection to an exchange point.

Data Center Interconnects (DCI)

A Data Center Interconnect (DCI) is similar in theory to a cross-connect, but uses electronics, typically DWDM, to establish a point-to-point connection between two data centers so they can share resources or improve other operations such as load balancing. For example, a company could choose to connect two different networks in the same metro or in two different metros.

Data Center Interconnection (DCI) can connect any data center whether it’s in proximity or located a great distance apart depending on the technology used to deliver the connectivity, Optical Networking, or Ethernet.

Internet Connectivity

As the name implies, internet connectivity lets data center customers access and use the internet. Yet, this is more than just a basic internet connection. There are multiple ways of delivering internet connectivity, Dedicated Internet Access (DIA), or IP Transit. While DIA provides basic connectivity, IP Transit is more advanced and leverages the BGP protocol. This enables the company to advertise its own IP Prefixes, and control how routing information is used.

Cloud Connectivity

Cloud connectivity refers to the ability of any company to connect to its virtual computing environment hosted by a public cloud provider (AWS, Microsoft, Google Cloud Platform) to access their data and workloads. While many companies may have assets such as compute, data storage, services, and more in the data center, their app may be in the cloud. They need a private connection between all of these to aid with issues such as bandwidth, reliability, and security.

There are several ways to establish these types of cloud connections

• Cloud on-ramps: These connections are powered by the network equipment the cloud provider deploys. Yet, they might not be available in all data centers because the high number of data centers in a particular region or metro quickly makes this option cost prohibitive. For companies in a data center with a cloud on-ramp, they can easily access it using a cross-connect.

• Network as a Service (NaaS): For those companies whose data centers don’t have cloud on-ramps, they can use NaaS platforms to accomplish the same goals. NaaS platforms are similar to IXPs: a switch companies can use to connect to other cloud on-ramps.
– VPN: Companies can also connect virtual private clouds to remote networks using many different VPN connectivity options, including site-to-site VPNs, provider-specific VPNs or third-party VPN software.

Any of these options helps companies access public cloud environments in an efficient, reliable, and secure way.

Clarity is Key

We hope these definitions and examples help you understand the various options available as you evaluate interconnection possibilities in a colocation facility. Stay tuned for the next article in the Interconnection blog series.

Related Resources

Northern Virginia Data Centers
DataBank Completing $4 Million Minneapolis Data Center Upgrade
What Is the Meaning of Interconnection in IT?
Interconnection 101—Getting Back to Connectivity Basics